Time one changed (3)

I believe the answer is:

eon

'time' is the definition.
(I know that eon is a type of geologic time)

'one changed' is the wordplay.
'changed' indicates an anagram.
'one' anagrammed gives 'EON'.

(Other definitions for eon that I've seen before include "Age, epoch" , "Vast period" , "Major division of geological time" , "Long period of time" , "An immense time" .)

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

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