Bellowing voice: hard to see where it is coming from? (7)

I believe the answer is:

foghorn

I'm a little stuck... Click here to teach me more about this clue!

'it is coming from?' is the definition.
The definition suggests a singular noun which matches the answer.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for foghorn that I've seen before include "Ship's hooter" , "Warning for ships" , "Warning device" , "Ship-warning siren" , "Ship warner" .)

I've seen this clue in The Guardian.

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.