diff --git a/cylc/flow/scripts/set.py b/cylc/flow/scripts/set.py
index c31b8f0b994..b6f50c1923c 100755
--- a/cylc/flow/scripts/set.py
+++ b/cylc/flow/scripts/set.py
@@ -39,7 +39,7 @@
     - expired does not imply other outputs
 
 CLI Completion:
-  Cylc can auto-complete prequisites and outputs for active tasks if you
+  Cylc can auto-complete prerequisites and outputs for active tasks if you
   specify the task in the command before attempting to complete these options.
 
 Examples: