Handle – transaction (4)
I believe the answer is:
deal
I believe this is a double definition.
'handle' is the first definition.
(dealing is a kind of handling)
'transaction' is the second definition.
(a deal is a transaction or exchange)
(Other definitions for deal that I've seen before include "Buy and sell" , "Give several people a hand" , "Trade; pine wood" , "Wood - piece of business" , "Pass around (e.g. cards)" .)