Ship's wheel (4)
I believe the answer is:
helm
'ship's wheel' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for helm that I've seen before include "Tiller; steer" , "Ship's steering apparatus" , "Tiller - part of armour" , "Steering gear" , "Steer (a boat/ship)" .)