Aunt almost protecting belly in fall (6)
I believe the answer is:
autumn
'fall' is the definition.
(I know that fall can be written as autumn)
'aunt almost protecting belly' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'protecting' is an insertion indicator (inserted letters are held or protected).
'belly' becomes 'tum' (I've seen this before).
'aunt' with its last letter removed is 'aun'.
'aun' enclosing 'tum' is 'AUTUMN'.
'in' acts as a link.
(Other definitions for autumn that I've seen before include "Season, has its music too (Keats)" , "Fall for 33 across" , "'O wild West Wind, thou breath of . . . . . . 's being' (Shelley)" , "Fall (over the pond?)" , "Fall in the US" .)