Crossword Genius

Bird's home into a sorting aid (10)

Ross

I believe the answer is:

pigeonhole

I'm a little stuck... Click here to teach me more about this clue!

'a sorting aid' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.

'bird's home' is the wordplay.
'bird' becomes 'pigeon' (type of bird).
'home' becomes 'hole' (I can't justify this - if you can you should believe this answer much more).
'pigeon'+'hole'='PIGEONHOLE'

'into' acts as a link.

Can you help me to learn more?

(Other definitions for pigeonhole that I've seen before include "Categorise" , "Classify; bird's home" , "Recess in loft" , "wherein one may put post" .)

I've seen this clue in the Sydney Morning Herald.
Want a hint initially instead of a full solution? Install my app