AskDefine | Define ounce

Dictionary Definition



1 a unit of apothecary weight equal to 480 grains or one twelfth of a pound [syn: troy ounce, apothecaries' ounce]
2 a unit of weight equal to one sixteenth of a pound or 16 drams or 28.349 grams [syn: oz.]
3 large feline of upland central Asia having long thick whitish fur [syn: snow leopard, Panthera uncia]

User Contributed Dictionary


Etymology 1

uncia, 1/12th part, from unus "one".



ounce, abbreviation oz.
  1. An avoirdupois ounce, weighing 1/16 of an avoirdupois pound, or 28.3495 grams.
  2. A troy ounce, weighing 1/12 of a troy pound, or 480 grains, or 31.1035 grams.
  3. A US fluid ounce, with a volume of 1/16 of a US pint, 1.804 687 cubic inches or 29.573 531 milliliters.
  4. A British imperial fluid ounce, with a volume of 1/20 of an imperial pint, 1.733871 cubic inches or 28.413063 milliliters.
28.3495 g
  • Arabic:
  • Chinese: 盎司 (àngsī)
  • Dutch: ons (=100 g)
  • Finnish: unssi
  • French: once
  • Galician: onza
  • German: Unze
  • Greek: ουγκιά (ougkiá)
  • Hungarian: uncia
  • Italian: oncia
  • Japanese: オンス (おんす, onsu)
  • Korean: 온스 (onseu)
  • Portuguese: onça
  • Russian: унция (úntsija)
  • Spanish: onza
  • Swedish: uns
Related terms

Etymology 2

Via French once, lonce, by false division (the l was thought to be the article), from Latin lynx, from (lunx), lynx. Interestingly, the taxon of the snow leopard is a Latinisation using the root of ounce (1).



Extensive Definition

This article is about the unit of mass. For the unit of force, see Pound-force. For the unit of volume, see Fluid ounce. For all other uses, see Ounce (disambiguation). The ounce (abbreviated: oz, the old Italian word onza, now spelled oncia) is a unit of mass in a number of different systems, including various systems of mass that form part of the imperial and United States customary systems. Its size can vary from system to system. The most commonly used ounces today are the international avoirdupois ounce and the international troy ounce.


Historically, in different parts of the world, at different points in time, and for different applications, the ounce (or its translation) has referred to broadly similar but different standards of mass (or weight, before the distinction between weight and mass developed). Some of these other ounces are described below.

International avoirdupois ounce

The avoirdupois ounce is the most commonly used ounce today. It is defined to be one sixteenth of an avoirdupois pound. It is therefore equal to 437.5 grains.
In 1958 the United States and countries of the Commonwealth of Nations agreed to define the international avoirdupois pound to be exactly 0.45359237 kilograms. Consequently, since 1958, the international avoirdupois ounce is exactly 28.349523125 grams by definition.
The ounce is commonly used as a unit of mass in the United States. While imperial units have been officially abolished in the United Kingdom, the ounce remains a familiar unit, especially amongst older people.

International troy ounce

A troy ounce (abbreviated as t oz) is equal to 480 grains. Consequently, the international troy ounce is equal to exactly 31.1034768 grams. There are 12 troy ounces in the now obsolete troy pound.
Today, the troy ounce is used only to express the mass of precious metals such as gold, platinum or silver.
For historical measurement of gold,
  • a fine ounce is a troy ounce of 99.5% (".995") pure gold
  • a standard ounce is a troy ounce of 22 carat gold, 91.66% pure (11 "fine ounces" plus one ounce of alloy material)

Apothecaries' ounce

The obsolete apothecaries' ounce (abbreviated ) equivalent to the troy ounce, was formerly used by apothecaries (now called pharmacists or chemists).

Maria Theresa ounce

"Maria Theresa ounce" was once introduced in Ethiopia and some European countries, which was equal to the weight of one Maria Theresa thaler, or 28.0668 g. Both the weight and the value are the definition of one "Birr", still in use in present-day Ethiopia and formerly in Eritrea.

Metric ounces

Some countries have redefined their ounces to fit in with the metric system.
The Dutch have redefined their ounce (in Dutch, ons) as 100 grams. Also the Avoirdupois pound (in Dutch pond) was redefined to 500 grams. This was adopted along with the introduction of the metric system and remains in informal usage (mostly in cookery and groceries). The Dutch's metric values, such as 1 ons = 100 grams, is inherited, adopted and taught in Indonesia since elementary school. It is also formally written in Indonesian national dictionary ( Kamus Besar Bahasa Indonesia ) and elementary school's formal manual book.
East Asia has a traditional ounce, known as a tael, of varying value. In China, it has been given a metric value of 50 grams.

Notes and references

External links

ounce in Arabic: أوقية
ounce in Bosnian: Unča
ounce in Czech: Unce
ounce in Danish: Unse
ounce in German: Unze
ounce in Spanish: Onza (unidad de masa)
ounce in Esperanto: Unco
ounce in Basque: Ontza (unitatea)
ounce in Persian: اونس
ounce in French: Once
ounce in Scottish Gaelic: Ùnnsa
ounce in Italian: Oncia (unità di misura)
ounce in Korean: 온스
ounce in Macedonian: Унца
ounce in Malay (macrolanguage): Auns
ounce in Dutch: Ons (massa)
ounce in Japanese: オンス
ounce in Norwegian: Unse
ounce in Polish: Uncja
ounce in Portuguese: Onça (peso)
ounce in Russian: Унция
ounce in Simple English: Ounce
ounce in Serbian: Унца
ounce in Finnish: Unssi
ounce in Swedish: Uns
ounce in Thai: ออนซ์
ounce in Vietnamese: Ounce
ounce in Turkish: Ons
ounce in Urdu: اونس
ounce in Chinese: 盎司

Synonyms, Antonyms and Related Words

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