A teaspoon is a small spoon suitable for stirring and sipping the contents of a cup of tea or coffee, or adding a portion of loose sugar. The heads of these spoons are more or less oval. Teaspoons are a common part of venue settings.
Long-handled teaspoons, such as iced teaspoons, are also commonly used in ice cream desserts or floats. Similar spoons include tablespoons and dessert spoons, the latter sized between a teaspoon and a tablespoon and used for eating desserts and sometimes soups or cereals. Less common is the coffee spoon, which is a smaller version of the teaspoon and works well in small coffee cups. Another teaspoon, called the orange spoon (American English: grapefruit spoon), tapers to a point or tooth and is used to separate citrus fruits from their membranes. A bar spoon, equivalent to a teaspoon, is used to measure the ingredients of mixed drinks.
A container for an extra teaspoon called a scoop was often grouped with a lidded sugar container and formed part of Victorian table service.
The teaspoon was first mentioned in an advertisement in the 1686 edition of the London Gazette.
In some countries, a teaspoon (sometimes "teaspoon") is a culinary measure, especially widely used in culinary recipes and medical prescriptions for medicines. In English, it is abbreviated as tsp. Or, less commonly, like t., ts., or tspn. Abbreviations are never capitalized because capital letters are usually reserved for larger spoons.
A metric teaspoon as a cooking measure is 5 mL, which equals 5 cm3, 1⁄3 UK/Canadian metric tablespoon, or 1⁄4 Australian metric tablespoon.
The United States customary unit
As a cooking unit of measure, a teaspoon is 1⁄3 tablespoon in the US, exactly 4.92892159375 ml, 1 1⁄3 US liquid dram, 1⁄6 US fluid ounce, 1⁄48 US cup, 1⁄768 US liquid gallon, or 77⁄256 (0.30078125) cubic inches.
For nutrition labels and medicines in the United States, a teaspoon is defined the same as a metric teaspoon, which is 5 milliliters (mL).
For dry ingredients (e.g. salt, flour, spices), if a recipe calls for a horizontal teaspoon, it refers to the roughly horizontal filling of the spoon, yielding the same volume as the liquid. A round teaspoon is a larger, but less precise measure, created by stacking ingredients as high as possible without flattening them. A heaping (North American English) or heaping (British English) teaspoon is a larger imprecise measure that includes the amount obtained by scooping up dry ingredients without flattening them. For some ingredients, such as flour, this amount can vary widely.
An unofficial but once widely used unit of apothecary measure, a teaspoon is equal to 1 fluid dram (or drachm), and thus equals 1⁄4 tablespoon or 1⁄8 fluid ounce. Apothecary's teaspoon is officially named from the Latin cochleare minus to distinguish it from the tablespoon or cochleare majus.
When tea-drinking was first introduced in England around 1660, tea was so rare and expensive that cups and spoons were smaller than they are today. This continued until 1784 when the Tax Cuts Act lowered the tea tax from 119% to 12.5%. As tea prices have fallen, teacup and teaspoon sizes have increased. By the 1850s, the teaspoon as a culinary unit of the measure had increased to 1⁄3 tablespoon, but the apothecary's unit of the measure remained the same. Nonetheless, the teaspoon, usually named by its Latin name, continued to be used in pharmacists' measurements over the following decades, with the original definition being a liquid dram.