Dog to reach across field without boundaries (7)
I believe the answer is:
spaniel
'dog' is the definition.
(spaniel is a kind of dog)
'reach across field without boundaries' is the wordplay.
I cannot really see how this works, but
'reach' could be 'span' (I've seen this in another clue) and 'span' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for spaniel that I've seen before include "Breed of dog" , "Dog found among the alpines" , "Dog with long silky coat" , "[HOUND]" , "Droopy-ear dog" .)