a cup in which tea is served, usually of small or moderate size.
tempest in a teacup / teapot, a disturbance or uproar about little or nothing: The fight over who should become the next assistant treasurer of the organization is just a tempest in a teacup. Also, storm in a teacup.
a cup out of which tea may be drunk, larger than a coffee cup
Also called teacupful. the amount a teacup will hold, about four fluid ounces