Woman taking step to identify plains (6)
I believe the answer is:
pampas
'plains' is the definition.
(I have seen 'Argentinian plains' mean 'pampas' so perhaps 'plains' could also mean 'pampas')
'woman taking step' is the wordplay.
'woman' becomes 'pam' ().
'taking' means one lot of letters go next to another.
'step' becomes 'pas' (I've seen this before).
'pam'+'pas'='PAMPAS'
'to identify' acts as a link.
(Other definitions for pampas that I've seen before include "part of South America" , "Vast plains of South America" , "Great plains of S America (6)" , "Great plains of Argentina" , "Grassy plains of Argentine" .)