Guns associated with assault (7)

I believe the answer is:

battery

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

'associated with assault' is the definition.
(I've seen this before)

I don't understand the rest of the clue.

(Other definitions for battery that I've seen before include "Personal attack" , "Artillery subunit; extensive range (of things)" , "Accumulator" , "Device that converts chemical energy into electrical energy" , "it makes poultry grow faster" .)

I've seen this clue in the Evening Standard.

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.