Navigator's aid; extent (7)

I believe the answer is:

compass

(Other definitions for compass that I've seen before include "may be boxed" , "using R [ROSE] for direction" , "Course guide" , "Direction finder; scope" , "Navigational instrument" .)

I've seen this clue in the Sydney Morning Herald.

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.