Crossword Genius

Submarine instrument (9)

Ross

I believe the answer is:

periscope

(Other definitions for periscope that I've seen before include "overseer" , "Submarine viewing aid" , "Submarine's eye?" , "Submarine's viewer" , "Optical instrument" .)

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.