Gather a large number (5)

I believe the answer is:

amass

'gather' is the definition.
(amass can mean to collect or gather)

'a large number' is the wordplay.
'large number' becomes 'mass' (I've seen this before).
'a'+'mass'='AMASS'

(Other definitions for amass that I've seen before include "Get together" , "Accumulate, pile up" , "Put together" , "run up?" , "Gathers" .)

I've seen this clue in The Times.

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