Teacup (unit)

1 teacup is 5 British imperial fluid ounces.

[1] Five British culinary measurement units are related to the teacup: the tumbler (10 British imperial fluid ounces),[2][3] the breakfast cup (8 British imperial fluid ounces),[1][4] the cup (6 British imperial fluid ounces),[2] the coffee cup (2⁠1/2⁠ British imperial fluid ounces),[1] and the wine glass (2 British imperial fluid ounces).

Which of these six units is used depends on the quantity or volume of the ingredient: there is division of labour between these six units, like the tablespoon and the teaspoon.

British cookery books and recipes, especially those from the days before the UK’s partial metrication, commonly use two or more of the aforesaid units simultaneously: for example, the same recipe may call for a ‘tumblerful’ of one ingredient and a ‘wineglassful’ of another one; or a ‘breakfastcupful’ or ‘cupful’ of one ingredient, a ‘teacupful’ of a second one, and a ‘coffeecupful’ of a third one.

There is not a British imperial unit⁠–⁠based culinary measuring cup.