gear, gear wheel, geared wheel, cogwheel (noun)

a toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion

gearing, gear, geartrain, power train, train (noun)

wheelwork consisting of a connected set of rotating gears by which force is transmitted or motion or torque is changed

"the fool got his tie caught in the geartrain"

gear, gear mechanism (noun)

a mechanism for transmitting motion for some specific purpose (as the steering gear of a vehicle)

gear, paraphernalia, appurtenance (verb)

equipment consisting of miscellaneous articles needed for a particular operation or sport etc.

gear, pitch (verb)

set the level or character of

"She pitched her speech to the teenagers in the audience"

gear (Noun)

equipment or paraphernalia, especially that used for an athletic endeavor.

gear (Noun)

a wheel with grooves (teeth) engraved on the outer circumference, such that two such devices can interlock and convey motion from one to the other.

gear (Noun)

a particular combination or choice of interlocking gears, such that a particular gear ratio is achieved.

gear (Noun)

A configuration of the transmission of an motor car so as to achieve a particular ratio of engine to axle torque

gear (Noun)

stuff.

gear (Verb)

To fit with gears in order to achieve a desired gear ratio.

gear (Interjection)

(mostly British (Scouse)) great or fantastic

Gear

A gear or cogwheel is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, torque, and direction of a power source. The most common situation is for a gear to mesh with another gear; however, a gear can also mesh with a non-rotating toothed part, called a rack, thereby producing translation instead of rotation. The gears in a transmission are analogous to the wheels in a pulley. An advantage of gears is that the teeth of a gear prevent slipping. When two gears of unequal number of teeth are combined, a mechanical advantage is produced, with both the rotational speeds and the torques of the two gears differing in a simple relationship. In transmissions which offer multiple gear ratios, such as bicycles and cars, the term gear, as in first gear, refers to a gear ratio rather than an actual physical gear. The term is used to describe similar devices even when the gear ratio is continuous rather than discrete, or when the device does not actually contain any gears, as in a continuously variable transmission.