diff --git a/web/tests/activity.test.js b/web/tests/activity.test.js
index b2ce86a74b..7f2d978d09 100644
--- a/web/tests/activity.test.js
+++ b/web/tests/activity.test.js
@@ -183,9 +183,10 @@ test("huddle_data.process_loaded_messages", () => {
         {
             type: "stream",
         },
+        // direct message to myself
         {
             type: "private",
-            display_recipient: [{id: me.user_id}], // PM to myself
+            display_recipient: [{id: me.user_id}],
         },
         {
             type: "private",
@@ -246,7 +247,7 @@ function buddy_list_add(user_id, $stub) {
     $("#user_presences").set_find_results(sel, $stub);
 }
 
-test("PM_update_dom_counts", () => {
+test("direct_message_update_dom_counts", () => {
     const $count = $.create("alice-unread-count");
     const pm_key = alice.user_id.toString();
     const $li = $.create("alice stub");
diff --git a/web/tests/buddy_data.test.js b/web/tests/buddy_data.test.js
index 2061e9c6bb..f85fb47be6 100644
--- a/web/tests/buddy_data.test.js
+++ b/web/tests/buddy_data.test.js
@@ -240,7 +240,7 @@ test("compose fade interactions (missing topic)", () => {
     assert.equal(faded(), false);
 });
 
-test("compose fade interactions (PMs)", () => {
+test("compose fade interactions (direct messages)", () => {
     people.add_active_user(fred);
 
     set_presence(fred.user_id, "active");
@@ -252,8 +252,8 @@ test("compose fade interactions (PMs)", () => {
     // Don't fade if we're not in a narrow.
     assert.equal(faded(), false);
 
-    // Fade fred if we are narrowed to a PM narrow that does
-    // not include him.
+    // Fade fred if we are narrowed to a direct message narrow
+    // that does not include him.
     compose_fade_helper.set_focused_recipient({
         type: "private",
         to_user_ids: "9999999",
diff --git a/web/tests/compose_actions.test.js b/web/tests/compose_actions.test.js
index 15e1aa8c3f..1121bda408 100644
--- a/web/tests/compose_actions.test.js
+++ b/web/tests/compose_actions.test.js
@@ -188,7 +188,7 @@ test("start", ({override, override_rewire, mock_template}) => {
     assert.equal(compose_state.topic(), "");
     stream_data.clear_subscriptions();
 
-    // Start PM
+    // Start direct message
     compose_defaults = {
         private_message_recipient: "foo@example.com",
     };
@@ -251,7 +251,7 @@ test("respond_to_message", ({override, override_rewire, mock_template}) => {
     mock_template("inline_decorated_stream_name.hbs", false, () => {});
     mock_stream_header_colorblock();
 
-    // Test PM
+    // Test direct message
     const person = {
         user_id: 22,
         email: "alice@example.com",
diff --git a/web/tests/compose_ui.test.js b/web/tests/compose_ui.test.js
index b01886b271..27779ad886 100644
--- a/web/tests/compose_ui.test.js
+++ b/web/tests/compose_ui.test.js
@@ -204,7 +204,7 @@ run_test("compute_placeholder_text", () => {
         $t({defaultMessage: "Message #all > Test"}),
     );
 
-    // PM Narrows
+    // direct message narrows
     opts = {
         message_type: "private",
         stream: "",
@@ -233,7 +233,7 @@ run_test("compute_placeholder_text", () => {
     });
     assert.equal(compose_ui.compute_placeholder_text(opts), $t({defaultMessage: "Message Alice"}));
 
-    // Group PM
+    // group direct message
     opts.private_message_recipient = "alice@zulip.com,bob@zulip.com";
     assert.equal(
         compose_ui.compute_placeholder_text(opts),
diff --git a/web/tests/compose_validate.test.js b/web/tests/compose_validate.test.js
index 006c167416..cbc6cba280 100644
--- a/web/tests/compose_validate.test.js
+++ b/web/tests/compose_validate.test.js
@@ -175,7 +175,7 @@ test_ui("validate", ({override_rewire, mock_template}) => {
         $("#compose-textarea").val("foobarfoobar");
     }
 
-    // test validating private messages
+    // test validating direct messages
     compose_state.set_message_type("private");
 
     initialize_pm_pill();
diff --git a/web/tests/composebox_typeahead.test.js b/web/tests/composebox_typeahead.test.js
index 442e3dc2d5..dfbf32caf3 100644
--- a/web/tests/composebox_typeahead.test.js
+++ b/web/tests/composebox_typeahead.test.js
@@ -72,7 +72,7 @@ run_test("verify wildcard mentions typeahead for stream message", () => {
     assert.equal(mention_stream.special_item_text, "stream (translated: Notify stream)");
 });
 
-run_test("verify wildcard mentions typeahead for private message", () => {
+run_test("verify wildcard mentions typeahead for direct message", () => {
     compose_state.set_message_type("private");
     assert.equal(ct.broadcast_mentions().length, 2);
     const mention_all = ct.broadcast_mentions()[0];
@@ -1720,8 +1720,8 @@ test("message people", ({override, override_rewire}) => {
 });
 
 test("muted users excluded from results", () => {
-    // This logic is common to PM recipients as well as
-    // mentions typeaheads, so we need only test once.
+    // This logic is common to direct message recipients as
+    // well as mentions typeaheads, so we need only test once.
     let results;
     const opts = {
         want_broadcast: true,
@@ -1743,11 +1743,13 @@ test("muted users excluded from results", () => {
     assert.deepEqual(results, [mention_all, call_center]);
 });
 
-test("PM recipients sorted according to stream / topic being viewed", ({override_rewire}) => {
-    // This tests that PM recipient results are sorted with subscribers of
-    // the stream / topic being viewed being given priority. If no stream
-    // is being viewed, the sort is alphabetical (for testing, since we do not
-    // simulate PM history)
+test("direct message recipients sorted according to stream / topic being viewed", ({
+    override_rewire,
+}) => {
+    // This tests that direct message recipient results are sorted with
+    // subscribers of the stream / topic being viewed being given priority.
+    // If no stream is being viewed, the sort is alphabetical (for testing,
+    // since we do not simulate direct message history)
     let results;
 
     // Simulating just cordelia being subscribed to denmark.
diff --git a/web/tests/drafts.test.js b/web/tests/drafts.test.js
index 2b33a57120..74122f3146 100644
--- a/web/tests/drafts.test.js
+++ b/web/tests/drafts.test.js
@@ -78,7 +78,7 @@ const draft_2 = {
     private_message_recipient: "aaron@zulip.com",
     reply_to: "aaron@zulip.com",
     type: "private",
-    content: "Test private message",
+    content: "Test direct message",
 };
 const short_msg = {
     stream: "stream",
@@ -238,7 +238,7 @@ test("remove_old_drafts", () => {
         private_message_recipient: "aaron@zulip.com",
         reply_to: "aaron@zulip.com",
         type: "private",
-        content: "Test private message",
+        content: "Test direct message",
         updatedAt: new Date().setDate(-30),
     };
     const draft_model = drafts.draft_model;
@@ -507,7 +507,7 @@ test("format_drafts", ({override_rewire, mock_template}) => {
         private_message_recipient: "aaron@zulip.com",
         reply_to: "aaron@zulip.com",
         type: "private",
-        content: "Test private message",
+        content: "Test direct message",
         updatedAt: date(-1),
     };
     const draft_3 = {
@@ -521,14 +521,14 @@ test("format_drafts", ({override_rewire, mock_template}) => {
         private_message_recipient: "aaron@zulip.com",
         reply_to: "iago@zulip.com",
         type: "private",
-        content: "Test private message 2",
+        content: "Test direct message 2",
         updatedAt: date(-5),
     };
     const draft_5 = {
         private_message_recipient: "aaron@zulip.com",
         reply_to: "zoe@zulip.com",
         type: "private",
-        content: "Test private message 3",
+        content: "Test direct message 3",
         updatedAt: date(-2),
     };
 
@@ -550,21 +550,21 @@ test("format_drafts", ({override_rewire, mock_template}) => {
             draft_id: "id2",
             is_stream: false,
             recipients: "Aaron",
-            raw_content: "Test private message",
+            raw_content: "Test direct message",
             time_stamp: "Jan 30",
         },
         {
             draft_id: "id5",
             is_stream: false,
             recipients: "Aaron",
-            raw_content: "Test private message 3",
+            raw_content: "Test direct message 3",
             time_stamp: "Jan 29",
         },
         {
             draft_id: "id4",
             is_stream: false,
             recipients: "Aaron",
-            raw_content: "Test private message 2",
+            raw_content: "Test direct message 2",
             time_stamp: "Jan 26",
         },
         {
@@ -656,7 +656,7 @@ test("filter_drafts", ({override_rewire, mock_template}) => {
         private_message_recipient: "aaron@zulip.com",
         reply_to: "aaron@zulip.com",
         type: "private",
-        content: "Test private message",
+        content: "Test direct message",
         updatedAt: date(-1),
     };
     const stream_draft_2 = {
@@ -670,14 +670,14 @@ test("filter_drafts", ({override_rewire, mock_template}) => {
         private_message_recipient: "aaron@zulip.com",
         reply_to: "iago@zulip.com",
         type: "private",
-        content: "Test private message 2",
+        content: "Test direct message 2",
         updatedAt: date(-5),
     };
     const pm_draft_3 = {
         private_message_recipient: "aaron@zulip.com",
         reply_to: "zoe@zulip.com",
         type: "private",
-        content: "Test private message 3",
+        content: "Test direct message 3",
         updatedAt: date(-2),
     };
 
@@ -686,21 +686,21 @@ test("filter_drafts", ({override_rewire, mock_template}) => {
             draft_id: "id2",
             is_stream: false,
             recipients: "Aaron",
-            raw_content: "Test private message",
+            raw_content: "Test direct message",
             time_stamp: "Jan 30",
         },
         {
             draft_id: "id5",
             is_stream: false,
             recipients: "Aaron",
-            raw_content: "Test private message 3",
+            raw_content: "Test direct message 3",
             time_stamp: "Jan 29",
         },
         {
             draft_id: "id4",
             is_stream: false,
             recipients: "Aaron",
-            raw_content: "Test private message 2",
+            raw_content: "Test direct message 2",
             time_stamp: "Jan 26",
         },
     ];
diff --git a/web/tests/echo.test.js b/web/tests/echo.test.js
index a83cd893e7..0974408999 100644
--- a/web/tests/echo.test.js
+++ b/web/tests/echo.test.js
@@ -249,7 +249,7 @@ run_test("insert_local_message streams", ({override, override_rewire}) => {
     assert.ok(insert_message_called);
 });
 
-run_test("insert_local_message PM", ({override, override_rewire}) => {
+run_test("insert_local_message direct message", ({override, override_rewire}) => {
     const local_id_float = 102.01;
 
     page_params.user_id = 123;
diff --git a/web/tests/example3.test.js b/web/tests/example3.test.js
index 50365c1c2c..8febbef88a 100644
--- a/web/tests/example3.test.js
+++ b/web/tests/example3.test.js
@@ -7,9 +7,9 @@ const {run_test} = require("./lib/test");
 const {page_params} = require("./lib/zpage_params");
 
 // In the Zulip app you can narrow your message stream by topic, by
-// sender, by PM recipient, by search keywords, etc.  We will discuss
-// narrows more broadly, but first let's test out a core piece of
-// code that makes things work.
+// sender, by direct message recipient, by search keywords, etc.
+// We will discuss narrows more broadly, but first let's test out a
+// core piece of code that makes things work.
 
 const {Filter} = zrequire("../src/filter");
 const stream_data = zrequire("stream_data");
diff --git a/web/tests/example8.test.js b/web/tests/example8.test.js
index e8565ef0b9..d8ab51e060 100644
--- a/web/tests/example8.test.js
+++ b/web/tests/example8.test.js
@@ -73,7 +73,7 @@ run_test("typing_events.render_notifications_for_narrow", ({override, mock_templ
     // All typists are rendered in `#typing_notifications`.
     const $typing_notifications = $("#typing_notifications");
 
-    // Narrow to a PM group with four users.
+    // Narrow to a group direct message with four users.
     override(page_params, "user_id", anna.user_id);
     const group = [anna.user_id, vronsky.user_id, levin.user_id, kitty.user_id];
     const group_emails = `${anna.email},${vronsky.email},${levin.email},${kitty.email}`;
diff --git a/web/tests/message_edit.test.js b/web/tests/message_edit.test.js
index ea94a7aa4f..e1d34e62a3 100644
--- a/web/tests/message_edit.test.js
+++ b/web/tests/message_edit.test.js
@@ -235,7 +235,7 @@ run_test("stream_and_topic_exist_in_edit_history", () => {
     // A non-stream message (object has no stream_id or topic)
     // with content edit history, should return false.
     const private_message = {
-        edit_history: [{prev_content: "content edit to PM"}],
+        edit_history: [{prev_content: "content edit to direct message"}],
     };
     assert.equal(
         message_edit.stream_and_topic_exist_in_edit_history(private_message, 1, "topic match"),
diff --git a/web/tests/message_list_data.test.js b/web/tests/message_list_data.test.js
index 91c5055c19..fc89a2fca9 100644
--- a/web/tests/message_list_data.test.js
+++ b/web/tests/message_list_data.test.js
@@ -133,15 +133,22 @@ run_test("muting", () => {
     const msgs = [
         {id: 1, type: "stream", stream_id: 1, topic: "muted"},
         {id: 2, type: "stream", stream_id: 1, topic: "whatever"},
-        {id: 3, type: "stream", stream_id: 1, topic: "muted", mentioned: true}, // mentions override muting
+        // mentions override muting
+        {id: 3, type: "stream", stream_id: 1, topic: "muted", mentioned: true},
 
         // 10 = muted user, 9 = non-muted user, 11 = you
-        {id: 4, type: "private", to_user_ids: "9,10,11", sender_id: 10}, // muted to huddle
-        {id: 5, type: "private", to_user_ids: "9,10,11", sender_id: 9}, // non-muted to huddle
-        {id: 6, type: "private", to_user_ids: "11", sender_id: 10}, // muted to 1:1 PM
-        {id: 7, type: "private", to_user_ids: "11", sender_id: 9}, // non-muted to 1:1 PM
-        {id: 8, type: "private", to_user_ids: "10", sender_id: 11}, // 1:1 PM to muted
-        {id: 9, type: "private", to_user_ids: "9", sender_id: 11}, // 1:1 PM to non-muted
+        // muted to group direct message
+        {id: 4, type: "private", to_user_ids: "9,10,11", sender_id: 10},
+        // non-muted to group direct message
+        {id: 5, type: "private", to_user_ids: "9,10,11", sender_id: 9},
+        // muted to 1:1 direct message
+        {id: 6, type: "private", to_user_ids: "11", sender_id: 10},
+        // non-muted to 1:1 direct message
+        {id: 7, type: "private", to_user_ids: "11", sender_id: 9},
+        // 1:1 direct message to muted
+        {id: 8, type: "private", to_user_ids: "10", sender_id: 11},
+        // 1:1 direct message to non-muted
+        {id: 9, type: "private", to_user_ids: "9", sender_id: 11},
     ];
 
     user_topics.update_user_topics(1, "muted", user_topics.all_visibility_policies.MUTED);
@@ -151,8 +158,8 @@ run_test("muting", () => {
     // messages if `excludes_muted_topics` is false.
     assert.deepEqual(mld.messages_filtered_for_topic_mutes(msgs), msgs);
 
-    // If we are in a 1:1 PM narrow, `messages_filtered_for_user_mutes` should skip
-    // filtering messages.
+    // If we are in a 1:1 direct message narrow, `messages_filtered_for_user_mutes`
+    // should skip filtering messages.
     assert.deepEqual(mld.messages_filtered_for_user_mutes(msgs), msgs);
 
     // Test actual behaviour of `messages_filtered_for_*` methods.
@@ -163,7 +170,7 @@ run_test("muting", () => {
         {id: 2, type: "stream", stream_id: 1, topic: "whatever"},
         {id: 3, type: "stream", stream_id: 1, topic: "muted", mentioned: true}, // mentions override muting
 
-        // `messages_filtered_for_topic_mutes` does not affect private messages
+        // `messages_filtered_for_topic_mutes` does not affect direct messages
         {id: 4, type: "private", to_user_ids: "9,10,11", sender_id: 10},
         {id: 5, type: "private", to_user_ids: "9,10,11", sender_id: 9},
         {id: 6, type: "private", to_user_ids: "11", sender_id: 10},
@@ -178,11 +185,14 @@ run_test("muting", () => {
         {id: 1, type: "stream", stream_id: 1, topic: "muted"},
         {id: 2, type: "stream", stream_id: 1, topic: "whatever"},
         {id: 3, type: "stream", stream_id: 1, topic: "muted", mentioned: true},
-
-        {id: 4, type: "private", to_user_ids: "9,10,11", sender_id: 10}, // muted to huddle
-        {id: 5, type: "private", to_user_ids: "9,10,11", sender_id: 9}, // non-muted to huddle
-        {id: 7, type: "private", to_user_ids: "11", sender_id: 9}, // non-muted to 1:1 PM
-        {id: 9, type: "private", to_user_ids: "9", sender_id: 11}, // 1:1 PM to non-muted
+        // muted to group direct message
+        {id: 4, type: "private", to_user_ids: "9,10,11", sender_id: 10},
+        // non-muted to group direct message
+        {id: 5, type: "private", to_user_ids: "9,10,11", sender_id: 9},
+        // non-muted to 1:1 direct message
+        {id: 7, type: "private", to_user_ids: "11", sender_id: 9},
+        // 1:1 direct message to non-muted
+        {id: 9, type: "private", to_user_ids: "9", sender_id: 11},
     ]);
 
     // Output filtered based on both topic and user muting.
diff --git a/web/tests/pm_conversations.test.js b/web/tests/pm_conversations.test.js
index 924dcbaf86..e47806e89c 100644
--- a/web/tests/pm_conversations.test.js
+++ b/web/tests/pm_conversations.test.js
@@ -58,7 +58,8 @@ test("insert_recent_private_message", () => {
     // Insert new messages (which should rearrange these entries).
     pmc.recent.insert([1], 1000);
     pmc.recent.insert([1, 2, 3], 999);
-    pmc.recent.insert([], 101); // Self-PM
+    // direct message to oneself
+    pmc.recent.insert([], 101);
 
     // Try to backdate user1's latest message.
     pmc.recent.insert([1], 555);
@@ -91,7 +92,7 @@ test("muted_users", () => {
     muted_users.add_muted_user(2);
 
     // We should now get back only those messages which are either-
-    // 1:1 PMs in which the other user hasn't been muted.
+    // 1:1 direct messages in which the other user hasn't been muted.
     // Huddles where there's at least one non-muted participant.
     assert.deepEqual(pmc.recent.get(), [
         {user_ids_string: "3", max_message_id: 99},
diff --git a/web/tests/pm_list_data.test.js b/web/tests/pm_list_data.test.js
index b554b01a6d..c2a73b2155 100644
--- a/web/tests/pm_list_data.test.js
+++ b/web/tests/pm_list_data.test.js
@@ -248,7 +248,7 @@ test("get_list_info_unread_messages", ({override}) => {
         "Bob",
     ]);
 
-    // Narrowing to private messages with Alice adds older
+    // Narrowing to direct messages with Alice adds older
     // one-on-one conversation with her to the list and one
     // unread is removed from more_conversations_unread_count.
     set_pm_with_filter("alice@zulip.com");
@@ -325,7 +325,7 @@ test("get_list_info_no_unread_messages", ({override}) => {
         "Bob",
     ]);
 
-    // Narrowing to private messages with Alice adds older
+    // Narrowing to direct messages with Alice adds older
     // one-on-one conversation with her to the list.
     set_pm_with_filter("alice@zulip.com");
     list_info = pm_list_data.get_list_info(false);
diff --git a/web/tests/recent_senders.test.js b/web/tests/recent_senders.test.js
index bfdca9ef40..74fc8675a0 100644
--- a/web/tests/recent_senders.test.js
+++ b/web/tests/recent_senders.test.js
@@ -340,7 +340,7 @@ test("process_pms", () => {
         participants: [1, 3, 2],
         non_participants: [4],
     });
-    // PM doesn't exist.
+    // Direct message doesn't exist.
     assert.deepEqual(rs.get_pm_recent_senders("1000,2000"), {
         participants: [],
         non_participants: [],
diff --git a/web/tests/recent_topics.test.js b/web/tests/recent_topics.test.js
index 86f2cf86f2..fe562173de 100644
--- a/web/tests/recent_topics.test.js
+++ b/web/tests/recent_topics.test.js
@@ -871,7 +871,7 @@ test("basic assertions", ({mock_template, override_rewire}) => {
         "4:topic-10,1:topic-7,1:topic-6,1:topic-5,1:topic-4,1:topic-3,1:topic-2,1:topic-1",
     );
 
-    // Process private message
+    // Process direct message
     rt_data.process_message({
         type: "private",
         to_user_ids: "6,7,8",
diff --git a/web/tests/typeahead_helper.test.js b/web/tests/typeahead_helper.test.js
index 9bf6e2772f..6f7fb31122 100644
--- a/web/tests/typeahead_helper.test.js
+++ b/web/tests/typeahead_helper.test.js
@@ -334,7 +334,7 @@ test("sort_recipients", () => {
         "a_bot@zulip.com",
     ]);
 
-    // Typeahead for private message [query, "", ""]
+    // Typeahead for direct message [query, "", ""]
     assert.deepEqual(get_typeahead_result("a", "", ""), [
         "a_user@zulip.org",
         "a_bot@zulip.com",
@@ -352,7 +352,7 @@ test("sort_recipients", () => {
     peer_data.add_subscriber(1, people.get_user_id(subscriber_email_2));
     peer_data.add_subscriber(1, people.get_user_id(subscriber_email_3));
 
-    // For splitting based on whether a PM was sent
+    // For splitting based on whether a direct message was sent
     pm_conversations.set_partner(5);
     pm_conversations.set_partner(6);
     pm_conversations.set_partner(2);
@@ -524,7 +524,7 @@ test("sort_recipients dup alls", () => {
     assertSameEmails(recipients, expected);
 });
 
-test("sort_recipients dup alls private", () => {
+test("sort_recipients dup alls direct message", () => {
     compose_state.set_message_type("private");
     const all_obj = ct.broadcast_mentions()[0];
 
@@ -597,7 +597,7 @@ test("sort broadcast mentions for stream message type", () => {
     );
 });
 
-test("sort broadcast mentions for private message type", () => {
+test("sort broadcast mentions for direct message type", () => {
     compose_state.set_message_type("private");
     const results = th.sort_people_for_relevance(ct.broadcast_mentions().reverse(), "", "");
 
@@ -630,7 +630,7 @@ test("test compare directly for stream message type", () => {
     assert.equal(th.compare_people_for_relevance(zman, all_obj), 1);
 });
 
-test("test compare directly for private message", () => {
+test("test compare directly for direct message", () => {
     compose_state.set_message_type("private");
     const all_obj = ct.broadcast_mentions()[0];
 
diff --git a/web/tests/user_topics.test.js b/web/tests/user_topics.test.js
index 8f3278a40f..291cc95784 100644
--- a/web/tests/user_topics.test.js
+++ b/web/tests/user_topics.test.js
@@ -50,7 +50,7 @@ function test(label, f) {
 }
 
 test("edge_cases", () => {
-    // private messages
+    // direct messages
     assert.ok(!user_topics.is_topic_muted(undefined, undefined));
 });