Every now and then, review approach to instrument (4)

I believe the answer is:

harp

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

'instrument' is the definition.
(harp is a kind of instrument)

I don't understand the rest of the clue.

(Other definitions for harp that I've seen before include "Stringed instrument" , "Heavenly instrument?" , "semitone higher, abandoning intro" , "Instrument for angel" , "Stick to one theme" .)

I've seen this clue in The Irish Times.

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.