A great deal of flotsam (3)

I believe the answer is:
lot
'a great deal' is the definition.
(both can mean a large amount)
'of flotsam' is the wordplay.
'of' indicates a hidden word.
'LOT' is hidden in the letters of 'flotsam'.
(Other definitions for lot that I've seen before include "Abraham's nephew - assigned share" , "Share - tons" , "Sale item(s); destiny" , "Destiny - auction item(s)" , "Survivor in Sodom" .)