Dog that is left by bridge (7)
I believe the answer is:
spaniel
'dog' is the definition.
(I've seen this before)
'that is left by bridge' is the wordplay.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'left' becomes 'l' (common abbreviation).
'by' is a charade indicator (letters next to each other).
'bridge' becomes 'span' ('span' can be a synonym of 'bridge'**).
'ie'+'l'='iel'
'iel' after 'span' is 'SPANIEL'.
(Other definitions for spaniel that I've seen before include "Springer- - -" , "Breed of dog" , "Dog with drooping ears" , "See 13" , "See 1 Across" .)