Longman Dictionary of Contemporary English
Wiktionary
n. (context British English) a social gathering where people talk over coffee and cakes, usually to raise money for a charity
Usage examples of "coffee morning".
She phoned Stuart and Elaine Duncan, putting off the mid-week invitation to dinner, a coffee morning, and all the others, but assuring them that soon she and Peter would be back into their social routine, his travelling permitting.
Mona McCarthy had been around wondering would Ria help at a coffee morning, which was fine except that it meant she would have to ask someone to look after Brian for her.
The medical workers are still out on strike, and it aint exactly a ladies' coffee morning.
Jacqueline realized she was referring to her pre-coffee morning grumpiness.
They must have thought theywere picking up guests from some huge coffee morning.