Heaps of terriers (6)
I believe the answer is:
cairns
This clue might be a double definition.
'heaps' is the first definition.
Although both the answer and definition are plural nouns, I can't see how one could define the other.
'terriers' is the second definition.
(cairn is a kind of terrier)
'of' is the link.
Can you help me to learn more?
(Other definitions for cairns that I've seen before include "Stone mounds" , "Heaps of stones - dogs" , "Pyramids of stones as monuments or landmarks" , "Memorial mounds of stones" , "Prehistoric burial mounds made of stones" .)