diff --git a/lib/types/message-types.js b/lib/types/message-types.js
--- a/lib/types/message-types.js
+++ b/lib/types/message-types.js
@@ -407,7 +407,7 @@
   //  1) getMessageInfosSince: Result set for thread is equal to max, and the
   //     truncation status isn't EXHAUSTIVE (ie. doesn't include the very first
   //     message).
-  //  2) getMessageInfos: ThreadSelectionCriteria does not specify cursors, the
+  //  2) getMessageInfos: MessageSelectionCriteria does not specify cursors, the
   //     result set for thread is equal to max, and the truncation status isn't
   //     EXHAUSTIVE. If cursors are specified, we never return truncated, since
   //     the cursor given us guarantees the contiguousness of the result set.
@@ -438,7 +438,7 @@
 
 export type ThreadCursors = { +[threadID: string]: ?string };
 
-export type ThreadSelectionCriteria = {
+export type MessageSelectionCriteria = {
   +threadCursors?: ?ThreadCursors,
   +joinedThreads?: ?boolean,
 };
diff --git a/server/src/creators/update-creator.js b/server/src/creators/update-creator.js
--- a/server/src/creators/update-creator.js
+++ b/server/src/creators/update-creator.js
@@ -458,13 +458,13 @@
     calendarQuery = defaultCalendarQuery(viewer.platform, viewer.timeZone);
   }
   if (threadIDsNeedingDetailedFetch.size > 0) {
-    const threadSelectionCriteria = { threadCursors: {} };
+    const messageSelectionCriteria = { threadCursors: {} };
     for (const threadID of threadIDsNeedingDetailedFetch) {
-      threadSelectionCriteria.threadCursors[threadID] = false;
+      messageSelectionCriteria.threadCursors[threadID] = false;
     }
     promises.messageInfosResult = fetchMessageInfos(
       viewer,
-      threadSelectionCriteria,
+      messageSelectionCriteria,
       defaultNumberPerThread,
     );
     const threadCalendarQuery = {
diff --git a/server/src/fetchers/message-fetchers.js b/server/src/fetchers/message-fetchers.js
--- a/server/src/fetchers/message-fetchers.js
+++ b/server/src/fetchers/message-fetchers.js
@@ -15,7 +15,7 @@
   messageTypes,
   type MessageType,
   assertMessageType,
-  type ThreadSelectionCriteria,
+  type MessageSelectionCriteria,
   type MessageTruncationStatus,
   messageTruncationStatus,
   type FetchMessageInfosResult,
@@ -245,10 +245,10 @@
 
 async function fetchMessageInfos(
   viewer: Viewer,
-  criteria: ThreadSelectionCriteria,
+  criteria: MessageSelectionCriteria,
   numberPerThread: number,
 ): Promise<FetchMessageInfosResult> {
-  const threadSelectionClause = threadSelectionCriteriaToSQLClause(criteria);
+  const selectionClause = messageSelectionCriteriaToSQLClause(criteria);
   const truncationStatuses = {};
 
   const viewerID = viewer.id;
@@ -280,7 +280,7 @@
           AND stm.thread = m.content AND stm.user = ${viewerID}
         WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
   `;
-  query.append(threadSelectionClause);
+  query.append(selectionClause);
   query.append(SQL`
         ORDER BY m.thread, m.time DESC
       ) x
@@ -345,7 +345,9 @@
   };
 }
 
-function threadSelectionCriteriaToSQLClause(criteria: ThreadSelectionCriteria) {
+function messageSelectionCriteriaToSQLClause(
+  criteria: MessageSelectionCriteria,
+) {
   const conditions = [];
   if (criteria.joinedThreads === true) {
     conditions.push(SQL`mm.role > 0`);
@@ -366,8 +368,8 @@
   return mergeOrConditions(conditions);
 }
 
-function threadSelectionCriteriaToInitialTruncationStatuses(
-  criteria: ThreadSelectionCriteria,
+function messageSelectionCriteriaToInitialTruncationStatuses(
+  criteria: MessageSelectionCriteria,
   defaultTruncationStatus: MessageTruncationStatus,
 ) {
   const truncationStatuses = {};
@@ -381,12 +383,12 @@
 
 async function fetchMessageInfosSince(
   viewer: Viewer,
-  criteria: ThreadSelectionCriteria,
+  criteria: MessageSelectionCriteria,
   currentAsOf: number,
   maxNumberPerThread: number,
 ): Promise<FetchMessageInfosResult> {
-  const threadSelectionClause = threadSelectionCriteriaToSQLClause(criteria);
-  const truncationStatuses = threadSelectionCriteriaToInitialTruncationStatuses(
+  const selectionClause = messageSelectionCriteriaToSQLClause(criteria);
+  const truncationStatuses = messageSelectionCriteriaToInitialTruncationStatuses(
     criteria,
     messageTruncationStatus.UNCHANGED,
   );
@@ -407,7 +409,7 @@
     WHERE m.time > ${currentAsOf} AND
       JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
   `;
-  query.append(threadSelectionClause);
+  query.append(selectionClause);
   query.append(SQL`
     ORDER BY m.thread, m.time DESC
   `);
diff --git a/server/src/responders/user-responders.js b/server/src/responders/user-responders.js
--- a/server/src/responders/user-responders.js
+++ b/server/src/responders/user-responders.js
@@ -252,7 +252,7 @@
   for (const watchedThreadID of request.watchedIDs) {
     threadCursors[watchedThreadID] = null;
   }
-  const threadSelectionCriteria = { threadCursors, joinedThreads: true };
+  const messageSelectionCriteria = { threadCursors, joinedThreads: true };
 
   const [
     threadsResult,
@@ -262,7 +262,7 @@
     currentUserInfo,
   ] = await Promise.all([
     fetchThreadInfos(viewer),
-    fetchMessageInfos(viewer, threadSelectionCriteria, defaultNumberPerThread),
+    fetchMessageInfos(viewer, messageSelectionCriteria, defaultNumberPerThread),
     calendarQuery ? fetchEntryInfos(viewer, [calendarQuery]) : undefined,
     fetchKnownUserInfos(viewer),
     fetchLoggedInUserInfo(viewer),
diff --git a/server/src/responders/website-responders.js b/server/src/responders/website-responders.js
--- a/server/src/responders/website-responders.js
+++ b/server/src/responders/website-responders.js
@@ -132,14 +132,14 @@
     endDate: initialNavInfo.endDate,
     filters: defaultCalendarFilters,
   };
-  const threadSelectionCriteria = { joinedThreads: true };
+  const messageSelectionCriteria = { joinedThreads: true };
   const initialTime = Date.now();
 
   const assetInfoPromise = getAssetInfo();
   const threadInfoPromise = fetchThreadInfos(viewer);
   const messageInfoPromise = fetchMessageInfos(
     viewer,
-    threadSelectionCriteria,
+    messageSelectionCriteria,
     defaultNumberPerThread,
   );
   const entryInfoPromise = fetchEntryInfos(viewer, [calendarQuery]);
diff --git a/server/src/socket/socket.js b/server/src/socket/socket.js
--- a/server/src/socket/socket.js
+++ b/server/src/socket/socket.js
@@ -426,14 +426,14 @@
     for (const watchedThreadID of watchedIDs) {
       threadCursors[watchedThreadID] = null;
     }
-    const threadSelectionCriteria = { threadCursors, joinedThreads: true };
+    const messageSelectionCriteria = { threadCursors, joinedThreads: true };
     const [
       fetchMessagesResult,
       { serverRequests, activityUpdateResult },
     ] = await Promise.all([
       fetchMessageInfosSince(
         viewer,
-        threadSelectionCriteria,
+        messageSelectionCriteria,
         oldMessagesCurrentAsOf,
         defaultNumberPerThread,
       ),
diff --git a/server/src/updaters/thread-updaters.js b/server/src/updaters/thread-updaters.js
--- a/server/src/updaters/thread-updaters.js
+++ b/server/src/updaters/thread-updaters.js
@@ -773,7 +773,7 @@
   };
   const newMessages = await createMessages(viewer, [messageData]);
 
-  const threadSelectionCriteria = {
+  const messageSelectionCriteria = {
     threadCursors: { [request.threadID]: false },
   };
 
@@ -789,7 +789,7 @@
   }
 
   const [fetchMessagesResult, fetchEntriesResult] = await Promise.all([
-    fetchMessageInfos(viewer, threadSelectionCriteria, defaultNumberPerThread),
+    fetchMessageInfos(viewer, messageSelectionCriteria, defaultNumberPerThread),
     calendarQuery ? fetchEntryInfos(viewer, [calendarQuery]) : undefined,
   ]);
   const rawEntryInfos = fetchEntriesResult && fetchEntriesResult.rawEntryInfos;