start

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

• intransitive verb To begin a movement, activity, or undertaking.
• intransitive verb To move on the initial part of a journey.
• intransitive verb To have a beginning; commence.
• intransitive verb To come quickly into view, life, or activity; spring forth.
• intransitive verb To have as an initial part or job.
• intransitive verb To move one's body or a part of it suddenly or involuntarily.
• intransitive verb Sports To be in the initial lineup of a game or race.
• intransitive verb To protrude or bulge.
• intransitive verb To become loosened or disengaged.
• intransitive verb To take the first step in doing: synonym: begin.
• intransitive verb To cause to come into being; make happen or originate.
• intransitive verb To set into motion, operation, or activity.
• intransitive verb To begin to attend.
• intransitive verb To cause (someone) to have an initial position or role.
• intransitive verb To play in the initial lineup of (a game).
• intransitive verb To put (a player) into the initial lineup of a game.
• intransitive verb To enter (a participant) into a race or game.
• intransitive verb To found; establish.
• intransitive verb To tend in an early stage of development.
• intransitive verb To rouse (game) from its hiding place or lair; flush.
• intransitive verb To cause to become displaced or loosened.
• noun An act of beginning; an initial effort.
• noun The beginning of a new construction project.
• noun A result of an initial effort.
• noun A place or time of beginning.
• noun A starting line for a race.
• noun A signal to begin a race.
• noun An instance of beginning a race.
• noun An instance of being in the starting lineup for a game, especially as a pitcher.
• noun A startled reaction or movement.
• noun A part that has become dislocated or loosened.
• noun A position of advantage over others, as in a race or an endeavor; a lead.
• noun An opportunity granted to pursue a career or course of action.
• idiom (start a family) To conceive or have a first child.
• idiom (start in on) To begin an activity regarding (something).
• idiom (start in on) To begin to criticize or complain about (someone or something).
• idiom (start something) To cause trouble.
• idiom (to start with) At the beginning; initially.
• idiom (to start with) In any case.

from The Century Dictionary.

• To move with a sudden involuntary jerk or twitch, as from a shock of surprise, fear, pain, or the like; give sudden involuntary expression to or indication of surprise, pain, fright, or any sudden emotion, by a quick convulsive movement of the body: as, he started at the sight.
• To make a sudden or unexpected change of place or position; rise abruptly or quickly; spring; leap, dart, or rush with sudden quickness: as, to start aside, backward, forward, out, or up; to start from one's seat.
• To set out; begin or enter upon action, course, career, or pursuit, as a journey or a race.
• To run; escape; get away.
• To lose hold; give way; swerve aside; be disloeated or moved from an intended position or direction; spring: as, the ship's timbers started.