Quantity produced by factory with one working? (7)
I believe the answer is:
million
'quantity' is the definition.
(million is a kind of quantity)
'by factory with one working?' is the wordplay.
'by' is a charade indicator (letters next to each other).
'factory' becomes 'mill' ('mill' can be a synonym of 'factory'**).
'with' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'working?' becomes 'on'.
'mill'+'i'='milli'
'milli'+'on' is 'MILLION'.
'produced' is the link.
(Other definitions for million that I've seen before include "Ten thousand hundreds" , "A thousand thousnad" , "A thousand thousands" , "One followed by six zeros" , "A power of 1 Down" .)