diff --git a/src/backend/backup/basebackup_incremental.c b/src/backend/backup/basebackup_incremental.c
index 957b70b692..4962bf1529 100644
--- a/src/backend/backup/basebackup_incremental.c
+++ b/src/backend/backup/basebackup_incremental.c
@@ -727,7 +727,7 @@ GetIncrementalFilePath(Oid dboid, Oid spcoid, RelFileNumber relfilenumber,
  *
  * If the return value is BACK_UP_FILE_FULLY, caller should back up the whole
  * file just as if this were not an incremental backup.  The contents of the
- * relative_block_numbers array is unspecified in this case.
+ * relative_block_numbers array are unspecified in this case.
  *
  * If the return value is BACK_UP_FILE_INCREMENTALLY, caller should include
  * an incremental file in the backup instead of the entire file. On return,