Dance apace (3-4)
I believe the answer is:
one-step
'dance' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for one-step that I've seen before include "Kind of foxtrot" , "Style of foxtrot" , "(Very short?) ballroom dance" , "Foxtrot's precursor" , "Vigorous dance" .)