Pigeonholes (6)
I believe the answer is:
labels
'pigeonholes' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for labels that I've seen before include "Appends a category to something or someone" , "Tags; classifies" , "'Trade names, of designers say (6)'" , "tags,brands" , "Present tags" .)