The story
From pink (“pale red; (rare) fashionable, smart”) + tea (“drink made by infusing dried leaves or buds of the tea plant in hot water; light midafternoon meal”).
Etymology from Wiktionary, CC BY-SA 4.0.
pink tea
Today it means: A fashionable formal tea party or other social gathering; specifically, one organized and attended chiefly by women to discuss matters of suffrage, raise funds for charity, etc. Full definition →