Chuckle about wife's ridiculously expensive purchase? (7)
I believe the answer is:
'ridiculously expensive purchase?' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'chuckle about wife's' is the wordplay.
'chuckle' becomes 'titter' (I've seen this before).
'about' indicates putting letters inside.
'wife' becomes 'w' (abbreviation).
'titter' enclosing 'w' is 'TWITTER'.
Can you help me to learn more?
(Other definitions for twitter that I've seen before include "Chirping (could be electronic!)" , "Palpitate" , "Sound like small birds" , "networking service" , "Chatter" .)