diff --git a/server/src/main/java/org/elasticsearch/index/shard/IndexShard.java b/server/src/main/java/org/elasticsearch/index/shard/IndexShard.java
index e78c5c9eb08d1..41d5c51d76ae1 100644
--- a/server/src/main/java/org/elasticsearch/index/shard/IndexShard.java
+++ b/server/src/main/java/org/elasticsearch/index/shard/IndexShard.java
@@ -193,7 +193,7 @@ public class IndexShard extends AbstractIndexShardComponent implements IndicesCl
 
     protected volatile ShardRouting shardRouting;
     protected volatile IndexShardState state;
-    protected volatile long pendingPrimaryTerm;
+    protected volatile long pendingPrimaryTerm; // see JavaDocs for getPendingPrimaryTerm
     protected volatile long operationPrimaryTerm;
     protected final AtomicReference<Engine> currentEngineReference = new AtomicReference<>();
     final EngineFactory engineFactory;