diff --git a/specs/merge/fork-choice.md b/specs/merge/fork-choice.md
index d5fa08ee2..83bba3adf 100644
--- a/specs/merge/fork-choice.md
+++ b/specs/merge/fork-choice.md
@@ -110,9 +110,11 @@ def on_block(store: Store, signed_block: SignedBeaconBlock) -> None:
 
     # [New in Merge]
     if is_merge_block(pre_state, block.body):
+        # Check the parent PoW block of execution payload is a valid terminal PoW block.
         pow_block = get_pow_block(block.body.execution_payload.parent_hash)
         pow_parent = get_pow_block(pow_block.parent_hash)
         assert is_valid_terminal_pow_block(pow_block, pow_parent)
+        # If `TERMINAL_BLOCK_HASH` is used as an override, the activation epoch must be reached.
         if TERMINAL_BLOCK_HASH != Hash32():
             assert compute_epoch_at_slot(block.slot) >= TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
 
diff --git a/specs/merge/validator.md b/specs/merge/validator.md
index e0066ddce..88bf96643 100644
--- a/specs/merge/validator.md
+++ b/specs/merge/validator.md
@@ -127,9 +127,10 @@ def prepare_execution_payload(state: BeaconState,
                               fee_recipient: ExecutionAddress,
                               execution_engine: ExecutionEngine) -> Optional[PayloadId]:
     if not is_merge_complete(state):
-        is_tbh_override_set = TERMINAL_BLOCK_HASH != Hash32()
-        if is_tbh_override_set and get_current_epoch(state.slot) < TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH:
-            # TBH is set but activation epoch is not yet reached, no prepare payload call is needed
+        is_terminal_block_hash_set = TERMINAL_BLOCK_HASH != Hash32()
+        is_activation_epoch_reached = get_current_epoch(state.slot) < TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
+        if is_terminal_block_hash_set and is_activation_epoch_reached:
+            # Terminal block hash is set but activation epoch is not yet reached, no prepare payload call is needed
             return None
 
         terminal_pow_block = get_terminal_pow_block(pow_chain)