Pace; ladder rung (4)
I believe the answer is:
step
This clue is a double definition.
'pace' is the first definition.
(I know that pace can be written as step)
'ladder rung' is the second definition.
(I've seen this in another clue)
(Other definitions for step that I've seen before include "Manner of walking" , "Foot movement" , "Rung, dance movement" , "Set foot down on pest" , "Pace (taken one at a time?)" .)