A teaspoon is a small spoon, or a spoon used in measuring, commonly used to stir the contents of a cup of tea or coffee. Teaspoons with longer handles are commonly used for ice cream. Other spoon sizes include the tablespoon and the dessert spoon. Much less common is the coffee spoon, which is a smaller version of the teaspoon. The tablespoon is a larger version of the teaspoon.
In some countries, the teaspoon is also used as a unit of volume, especially in cooking recipes and pharmaceutic prescriptions. It is abbreviated in English as t. or tsp. (German and Dutch: TL, from Teelöffel or Theelepel). It is often taken to mean 5 ml; in some countries this value is even defined in law, for example in the USA in 21CFR101.9(b)(5)(viii). The same definition is used in some other English-speaking countries (e.g., Australia, Canada, New Zealand, United Kingdom). Older definitions included 1/6 U.S. fl. oz (4.93 mL) in the USA and 1/8 Imperial fl. oz (3.55 mL) in Britain.
A related unit is
Common teaspoons for stirring drinks are not always designed to contain any standard volume. In practice, they may hold between 2.5 mL and 6 mL of liquid, so caution must be employed when using a teaspoon to measure a certain prescribed dose of a medicine. For this reason and in order to avoid dispensing errors, special measuring spoons are available that hold exactly 5 mL. The common teaspoon is always smaller than the tablespoon.
If a recipe calls for a teaspoon of a powder ingredient (salt, flour, etc.), this normally refers to an approximately levelled filling of the spoon, just like with liquids. For example, a teaspoon of salt for cooking purposes, is 5 mL or about 4.75 grams.
Some recipes also call for heaping (or heaped in British English) spoon measures. Such a heaping/heaped teaspoon, refers to an inexact volume of the required ingredient, obtained by scooping it up with a teaspoon and not levelling it off. The amount obtained by heaping a spoon can easily vary by more than a factor of two.