Scrap — small dog perhaps grabs bite (7)
I believe the answer is:
snippet
'scrap' is the definition.
(I've seen this before)
'small dog perhaps grabs bite' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'dog perhaps' becomes 'pet' (dogs are often kept as pets).
'grabs' indicates putting letters inside.
'bite' becomes 'nip' (nipping is a kind of biting).
's'+'pet'='spet'
'spet' enclosing 'nip' is 'SNIPPET'.
(Other definitions for snippet that I've seen before include "A cutting" , "Fair --, knitwear style" , "Small scrap" , "Small fragment" , "excerpt of literature?" .)