teaspoon /ˈtiːˌspuːn/noun 2verb 1forms 3 noun2 •A small spoon used to stir the contents of a cup or glass. •A unit of measure, equivalent to one-third of a tablespoon in the United States or one-quarter of a tablespoon in Australia, or roughly five milliliters. verb1 •To serve with a teaspoon.I teaspooned some sugar into my cup. formsteaspooned · teaspooning · teaspoons