It may be used in the theatre or thereabout (5)

I believe the answer is:

ether

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

'it may be used in the theatre or thereabout' is the definition.
The definition suggests a singular noun which matches the answer.

'it may be used in the theatre' is the wordplay.
'it may be' becomes 'ethe' (I can't explain this - if you can you should give a lot more credence to this answer).
'used in' indicates the central letters (the letters used on the inside of the word).
'the theatre' becomes 'Lyric' (Lyric Theatre in London).
The middle letter of 'lyric' is 'r'.
'ethe'+'r'='ETHER'

Can you help me to learn more?

(Other definitions for ether that I've seen before include "What's clear" , "Clear upper air" , "Light liquid used as anaesthetic" , "Chemical solvent" , "Imaginary interstellar medium" .)

I've seen this clue in The Globe and Mail.

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