Meal takes an age - unnecessarily (8)

I believe the answer is:

luncheon

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'meal takes an age unnecessarily' is the definition.
I can't tell whether this definition defines the answer.

'meal takes an age' is the wordplay.
'meal' becomes 'lunch' (lunch is a kind of meal).
'takes' means one lot of letters go next to another.
'an age' becomes 'eon' (eon is a kind of age).
'lunch'+'eon'='LUNCHEON'

Can you help me to learn more?

(Other definitions for luncheon that I've seen before include "formal occasion" , "Food" , "midday menu" , "part of formal board" , "Midday meal" .)

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

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