Selection called equitable at first (5)
I believe the answer is:
range
'selection' is the definition.
(a selection is a range of things)
'called equitable at first' is the wordplay.
'called' becomes 'rang' (called on the phone).
'at first' suggests taking the first letters.
The first letter of 'equitable' is 'e'.
'rang'+'e'='RANGE'
(Other definitions for range that I've seen before include "Area of variation" , "spectrum" , "Full choice of clothes" , "Ramble" , "Limit of effectiveness" .)