Dance round home gym backward (3-4)

I believe the answer is:
one-step
'dance' is the definition.
(I've seen this before)
'round home gym backward' is the wordplay.
'round' becomes 'o' (o is a circular letter).
'home' becomes 'nest' (a bird's home).
'gym backward' becomes 'ep' (I can't justify this - if you can you should believe this answer much more).
'o'+'nest'+'ep'='ONE-STEP'
Can you help me to learn more?
(Other definitions for one-step that I've seen before include "Vigorous dance" , "Kind of foxtrot" , "Foxtrot's precursor" , "Style of foxtrot" , "(Very short?) ballroom dance" .)
