oz

Oz, oz, or OZ has several unrelated uses in measurement, geography, and fiction. The most common references are as an abbreviation for ounce, a unit of weight; as a shorthand for Australia; and as the fictional realm of Oz in L. Frank Baum's novels and their adaptations.

As a unit of mass, the ounce appears in two main systems: avoirdupois and troy. An avoirdupois ounce equals 28.3495 grams, while a troy ounce equals 31.1035 grams. The ounce is widely used in the United States and other countries for body weight and many commodity masses. For liquids, the term fluid ounce is used, and its value differs between the US and UK measurement systems.

In Commonwealth usage, "Oz" is informal shorthand for Australia, used in media, culture, and sports. The origin of the nickname is informal and, while widely understood, is not tied to a single official source.

The term Oz is also strongly associated with The Wizard of Oz, a low- and high-profile part of popular culture. The original 1900 novel The Wonderful Wizard of Oz by L. Frank Baum spawned sequels, stage productions, and a series of film and television adaptations, most famously the 1939 film. The story centers on Dorothy and her companions in the magical land of Oz, where they undertake journeys to meet the Wizard and confront various encounters along the way.