Crossword Genius

Cage with label on — it's five-sided (8)

Ross

I believe the answer is:

pentagon

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

'five-sided' is the definition.
I can't tell whether this definition defines the answer.

'cage with label on' is the wordplay.
'cage' becomes 'pen' (both can mean an enclosure).
'with' is a charade indicator (letters next to each other).
'label' becomes 'tag' (synonyms).
'pen'+'tag'+'on'='PENTAGON'

'it's' acts as a link.

Can you help me to learn more?

(Other definitions for pentagon that I've seen before include "Figure - US military HQ" , "US building of high security" , "US military leaders" , "Headquarters of the US Defence Department" , "Figure in plane" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app