They identify Latin quotations (4)
I believe the answer is:
tags
'they' is the definition.
Both the definition and answer are plural nouns.
Maybe you can see an association between them that I can't see?
'identify latin quotations' is the wordplay.
'identify' becomes 'tag' (I've seen this in other clues).
'latin quotations' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'tag'+'s'='TAGS'
Can you help me to learn more?
(Other definitions for tags that I've seen before include "trite Latin quotations" , "They are able to identify" , "Labels; quotations" .)