Consider to be equivalent to (6)
I believe the answer is:
equate
'consider to be equivalent to' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for equate that I've seen before include "Correspond" , "'Compare, liken (6)'" , "Match" , "Make or be similar" , "Consider or describe as similar, equal, or analogous" .)