Fruit is gathered in the fall (6)
I believe the answer is:
raisin
'fruit' is the definition.
(raisin is a kind of fruit)
'is gathered in the fall' is the wordplay.
'gathered' indicates anagramming the letters.
'in' means one lot of letters goes inside another.
'the fall' becomes 'rain' (I've seen this before).
'is' anagrammed gives 'si'.
'si' placed within 'rain' is 'RAISIN'.
(Other definitions for raisin that I've seen before include "Dried grape used in cakes" , "An iris (anag)" , "sultana, say" , "Fruit for the Christmas cake" , "fruit product" .)