Artillery unit in an assault? (7)
I believe the answer is:
battery
I believe this clue is a triple definition!
'artillery' is the first definition.
(battery is a kind of artillery)
'unit' is the second definition.
(battery is a kind of unit)
'in' is a link.
'an assault?' is the third definition.
(synonyms)
(Other definitions for battery that I've seen before include "Source of charge" , "Personal attack" , "Accumulator" , "associated with assault" , "Group of cells (or guns)" .)