Range that is large for a dog (7)
I believe the answer is:
spaniel
'for a dog' is the definition.
(spaniel is a kind of dog)
'range that is large' is the wordplay.
'range' becomes 'span' (I've seen this in another clue).
'that is' becomes 'ie' (abbreviation for id est, 'that is' in Latin).
'large' becomes 'L' (eg in clothes sizes).
'span'+'ie'+'l'='SPANIEL'
(Other definitions for spaniel that I've seen before include "Dog - leaps in (anag)" , "Breed of dog" , "Springer- - -" , "Droopy-ear dog" , "Dog with long silky coat" .)