Measure pace (4)
I believe the answer is:
step
I believe this is a double definition.
'measure' is the first definition.
(I've seen this before)
'pace' is the second definition.
('step' can be a synonym of 'pace')
(Other definitions for step that I've seen before include "Pace - part of a procedure" , "Tread - stage" , "'Stage, rung (4)'" , "one stage of flight" , "Football" .)