diff --git a/specs/beacon-chain.md b/specs/beacon-chain.md
index 644a9b06b..56555792f 100644
--- a/specs/beacon-chain.md
+++ b/specs/beacon-chain.md
@@ -133,7 +133,7 @@ An `AttestationSignedData` has the following fields:
     'parent_hashes': ['hash32'],
     # Shard block hash
     'shard_block_hash': 'hash32',
-    # Slot of last justified block
+    # Slot of last justified block referenced in the attestation
     'justified_slot': 'int64'
 }
 ```