Deep open crack in a glacier (8)

I believe the answer is:

crevasse

(Other definitions for crevasse that I've seen before include "Sever sac (anag)" , "big split" , "Deep glacial fissure" , "13 in a glacier" , "Deep open crack as in glacier" .)

I've seen this clue in The Mirror.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.