(aviation) zero-zero, a term meaning no ceiling and no visibility

(Internet slang) Used to signify assent to a proposal without indicating a strong opinion.

0. / The origin, starting point, or fixed reference point, especially for a measurement. / (electrical engineering) The off or low bit state.

Under the Whyte notation system, a steam locomotive that is articulated in three parts, with a boiler mounted on the centre frame, and two steam engines mounted on separate frames, one on each end of the boiler, and each having an 0-4-0 wheel configuration.

(automotive) A performance measure for automobiles, that either measures elapsed time, or elapsed distance. The automobile starts from a standing start, accelerates to 60 mph (roughly 100 km/h), and then brakes to a stop.

Under the Whyte notation system, a simple form of steam locomotive, with three axles connecting six driving wheels, and no leading wheels or trailing wheels.

Under the Whyte notation system, a steam locomotive, with four axles connecting eight powered driving wheels, and no leading wheels or trailing wheels.

Under the Whyte notation system, a steam locomotive, with five axles connecting ten powered driving wheels, and no leading wheels or trailing wheels.

Under the Whyte notation system, a steam locomotive, with six axles connecting twelve powered driving wheels, and no leading wheels or trailing wheels.

Under the Whyte notation system, the simplest form of steam locomotive, with two axles and four driving wheels, and no leading wheels or trailing wheels.