teaspoon

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The common small spoon used especially in serving and consuming tea, coffee, and desserts.
• noun A household cooking measure equal to ¹/₃ tablespoon (about 5 milliliters).

from The Century Dictionary.

• noun A small spoon used with the tea-cup, or in similar ways: it is larger than the coffee-spoon and smaller than the dessert-spoon.

from the GNU version of the Collaborative International Dictionary of English.

• noun A small spoon used in stirring and sipping tea, coffee, etc., and for other purposes.
• noun same as teaspoonful.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a small spoon used to stir the contents of a cup or glass.
• noun a unit of measure, worth one-third of a tablespoon or roughly five milliliters.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun as much as a teaspoon will hold
• noun a small spoon used for stirring tea or coffee; holds about one fluid dram