Word formed from initials (7)
I believe the answer is:
acronym
'word formed from initials' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for acronym that I've seen before include "Mar cony (anag)" , "A word formed from the initial letters of others" , "NATO's one" , "laser, for example" , "Perhaps NATO" .)