Available on an arrow (2,4)

I believe the answer is:

on hand

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

'available' is the definition.
(similar in meaning)

'on an arrow' is the wordplay.
'an arrow' becomes 'hand' (I am not sure about this - if you are sure you should believe this answer much more).
'on'+'hand'='ON HAND'

Can you help me to learn more?

(Other definitions for on hand that I've seen before include "Where digits may be" , "Ready, available" , "Readily available" , "available for use" , "Available like wedding ring?" .)

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.