An international coalition, founded in 1945 and headquartered in New York City, that aims to promote global co-operation and maintain international order.

(In the SI system of units) Any unit derived from one of the seven base units of length (meter), mass (kilogram), time (second), electric current (ampere), thermodynamic temperature (kelvin), amount of substance (mole) and luminous intensity (candela).

Any standardized, reproducible unit that can be used to measure any physical property.

(trains) A locomotive with an engine, generator, and traction motors, but without a control cab.

(linear algebra) An identity matrix

(in the singular, formerly also plural) Ellipsis of United States of America. / (in the plural) The collection of individual states of the United States of America.

A durational pattern which occupies a period of time equal to a pulse or pulses on an underlying metric level.

A kingdom and sovereign state in Western Europe comprising the four countries of England, Scotland and Wales in the island of Great Britain, and Northern Ireland in the island of Ireland. Since 1922.

(mathematics) the interval [0,1], that is the set of all real numbers x such that zero is less than or equal to x and x is less than or equal to one / (telecommunications) symbol duration time.

(astronomy) 149,597,870,700 metres, the approximate mean distance from the Earth to the Sun (the semi-major axis of Earth's orbit), (symbol AU), used to measure distances in the solar system.