speed

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Physics The rate or a measure of the rate of motion, especially.
• noun Distance traveled divided by the time of travel.
• noun The limit of this quotient as the time of travel becomes vanishingly small; the first derivative of distance with respect to time.
• noun The magnitude of a velocity.
• noun Swiftness of action.
• noun The act of moving rapidly.
• noun The state of being in rapid motion; rapidity.
• noun A transmission gear or set of gears in a motor vehicle.
• noun A numerical expression of the sensitivity of a photographic film, plate, or paper to light.
• noun The capacity of a lens to accumulate light at an appropriate aperture.
• noun The length of time required or permitted for a camera shutter to open and admit light.
• noun Slang A stimulant drug, especially amphetamine or methamphetamine.
• noun Slang One that suits or appeals to a person's inclinations, skills, or character.
• noun Archaic Prosperity; luck.
• intransitive verb To go, move, or proceed quickly.
• intransitive verb To drive at a speed exceeding a legal limit.
• intransitive verb To pass quickly.
• intransitive verb To move, work, or happen at a faster rate; accelerate.
• intransitive verb Slang To be under the influence of a stimulant drug.
• intransitive verb To prove successful; prosper.
• intransitive verb To get along in a specified manner; fare.
• intransitive verb To cause to move or proceed quickly; hasten.
• intransitive verb To increase the speed or rate of; accelerate. Often used with up:
• intransitive verb To further, promote, or expedite (a legal action, for example).
• intransitive verb Archaic To help to succeed or prosper; aid.
• idiom (up to speed) Operating at maximum speed.
• idiom (up to speed) Producing something or performing at an acceptable rate or level.
• idiom Informal (up to speed) Fully informed; conversant.

from The Century Dictionary.

• noun Success; a successful course; prosperity in doing something; good fortune; luck: used either absolutely or relatively: as, to wish one good speed in an undertaking.
• noun Apromoter of success or progress; a speeder.
• noun Rapidity of movement; quickness of motion; swiftness: also used figuratively.
• noun Rate of progress or motion (whether fast or slow); comparative rapidity; velocity: as, moderate speed; a fast or a slow rate of speed; to regulate the speed of machines.
• noun In submarine rock-drilling, a leg or beam to which the drilling apparatus is attached.
• noun Synonyms Swiftness, Rapidity, etc. (see quickness), expedition.
• To advance toward a goal or a result; get on successfully; be fortunate; prosper; get on in general; make progress; fare; succeed.
• To get on rapidly; move with celerity; hasten in going; go quickly; hasten in doing something; act rapidly; hurry; be quick.
• To cause to advance toward success; favor the course or cause of; make prosperous.
• To push forward; carry toward a conclusion; promote; advance.
• To send or push forward in a course; promote the going or progress of; cause to go; aid in going.
• To give high speed to; put to speed; hasten the going or progress of; make or cause to be rapid in movement; give celerity to: also used reflexively.
• To give a certain (specified) speed to; also, to regulate the speed of; arrange for a certain rate of going; set for a determined rapidity.
• To send off or away; put forth; despatch on a course: as, an arrow sped from the bow.
• Hence To send or put out of the way; get rid of; send off; do for; in a specific use, to send out of the world; put to death; despatch; kill.
• To cause to be relieved: only in the passive.
• To disclose; unfold; explain.