In recipes, quantities of ingredients may be specified by mass (commonly called weight), by volume, or by count.
For most of history, most cookbooks did not specify quantities precisely, instead talking of "a nice leg of spring lamb", a "cupful" of lentils, a piece of butter "the size of a walnut", and "sufficient" salt. Informal measurements such as a "pinch", a "drop", or a "hint" (soupçon) continue to be used from time to time. In the US, Fannie Farmer introduced the more exact specification of quantities by volume in her 1896 Boston Cooking-School Cook Book.
United States customary units are a system of measurements commonly used in the United States. The U.S. customary system developed from English units which were in use in the British Empire before American independence. Consequently most U.S. units are virtually identical to the British imperial units. However, the British system was overhauled in 1824, changing the definitions of some units used there, so several differences exist between the two systems.
The majority of U.S. customary units were redefined in terms of the meter and the kilogram with the Mendenhall Order of 1893, and in practice, for many years before. These definitions were refined by the international yard and pound agreement of 1959. The U.S. primarily uses customary units in its commercial activities, while science, medicine, government, and many sectors of industry use metric units. The International System of Units (SI), the modern form of the metric system, is preferred for many uses by the National Institute of Standards and Technology (NIST).
The system of imperial units or the imperial system (also known as British Imperial) is the system of units first defined in the British Weights and Measures Act of 1824, which was later refined and reduced. The system came into official use across the British Empire. By the late 20th century, most nations of the former empire had officially adopted the metric system as their main system of measurement; however some Imperial units are still used in the United Kingdom and Canada.
A measuring spoon is a spoon used to measure an amount of an ingredient, either liquid or dry, when cooking. Measuring spoons may be made of plastic, metal, and other materials. They are available in many sizes, including teaspoon and tablespoon. In the U.S., a measuring spoon is number of pieces, especially four or six. This usually includes ¼, ½, and 1 teaspoons and 1 tablespoon.
In Japan, usually two spoons are used: a large spoon (大さじ Ōsaji ) and a small spoon (小さじ Kosaji or Shōsaji ). A large spoon is 15 milliliter, and a small spoon is 5 milliliter. Sometimes a much smaller spoon may be used, usually a 2.5 milliliter spoon. (½ small spoon)