rapidity in moving, going, traveling, proceeding, or performing; swiftness; celerity

the speed of light; the speed of sound.

relative rapidity in moving, going, etc.; rate of motion or progress

full speed ahead.

full, maximum, or optimum rate of motion

The car gets to speed in just nine seconds.

Automotive . a transmission gear ratio.

Photography .

Also called film speed. the sensitivity of a film or paper to light, measured by an ASA or DIN index, which assigns low numbers to slow film and higher numbers to faster film.

Also called shutter speed. the length of time a shutter is opened to expose film.

the largest opening at which a lens can be used.

Slang . a stimulating drug, as caffeine, ephedrine, or esp. methamphetamine or amphetamine.

Informal . a person or thing that is compatible with or typical of one's ability, personality, desires, etc.

My speed is writing postcards on the porch while everyone else is tearing around the tennis court.

Archaic . success or prosperity.

to promote the success of (an affair, undertaking, etc.); further, forward, or expedite.

to direct (the steps, course, way, etc.) with speed.

to increase the rate of speed of (usually fol. by up )

to speed up industrial production.

to bring to a particular speed, as a machine.

to cause to move, go, or proceed with speed.

to expedite the going of

to speed the parting guest.

Archaic . to cause to succeed or prosper.

to move, go, pass, or proceed with speed or rapidity.

to drive a vehicle at a rate that exceeds the legally established maximum

He was arrested for speeding.

to increase the rate of speed or progress (usually fol. by up ).

to get on or fare in a specified or particular manner.

Archaic . to succeed or prosper. ?

at full or top speed

at the greatest speed possible

We drove down the highway at full speed.

to the maximum of one's capabilities; with great rapidity

He worked at full speed.

up to speed

operating at full or optimum speed.

functioning or producing at an expected, acceptable, or competitive level; up to par

a new firm not yet up to speed.