The House of Lords, say? (4,5)
I believe the answer is:
peer group
This clue could be a double definition.
'the house' is the first definition.
The definition and answer can be both groups as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'lords say?' is the second definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'of' is the link.
Can you help me to learn more?
(Other definitions for peer group that I've seen before include "contemporaries - with 15d" , "Those of equal age and ability, often influential" , "Classmates, say" , "those of similar age" , "People like oneself" .)