twitch

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

• intransitive verb To draw, pull, or move suddenly and sharply; jerk.
• intransitive verb To move jerkily or spasmodically.
• intransitive verb To ache sharply from time to time; twinge.
• noun A sudden involuntary or spasmodic muscular movement.
• noun A sudden pulling; a tug.
• noun A sudden, sharp pain.

from The Century Dictionary.

• noun The quitch or quitch-grass, Agropyrum repens.
• To pull or draw with a hasty jerk; snatch; jerk away.
• To give a short, sudden pull or tug at; jerk at; cause to move quickly or spasmodically.
• To nip; squeeze; make fast; tie tightly.
• To be suddenly jerked; move or contract quickly or spasmodically, as a muscle.
• To carp; sneer; make flings. Compare jerk, intransitive verb, 2.
• A dialectal variant of touch.
• noun A short, sharp pull or tug; a jerk or snatch.
• noun A short, spastic contraction of the fibers of muscles; a stitch; a twinge: as, a twitch in the side; convulsive twitches; especially, such a movement when causing pain: sometimes applied to moral pangs.
• noun A pair of nippers or tweezers.
• noun A noose attached to a stock or handle and twisted around the upper lip of a horse so as to bring him under command when shoeing or clipping: an instrument used for holding a vicious horse.
• noun In mining, a sudden narrowing of a vein so that the walls come nearly or quite together.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of twitching; a pull with a jerk; a short, sudden, quick pull.
• noun A short, spastic contraction of the fibers or muscles; a simple muscular contraction.
• noun (Far.) A stick with a hole in one end through which passes a loop, which can be drawn tightly over the upper lip or an ear of a horse. By twisting the stick the compression is made sufficiently painful to keep the animal quiet during a slight surgical operation.
• transitive verb To pull with a sudden jerk; to pluck with a short, quick motion; to snatch.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun couch grass, a species of grass, often considered as a weed.
• noun A brief, small (sometimes involuntary) movement out of place and then back again; a spasm.
• noun informal Action of spotting or seeking out a bird, especially a rare one.
• noun A stick with a hole in one end through which passes a loop, which can be drawn tightly over the upper lip or an ear of a horse and twisted to keep the animal quiet during minor surgery.
• verb intransitive To perform a twitch; spasm.
• verb transitive To jerk sharply and briefly.
• verb transitive To spot or seek out a bird, especially a rare one.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb toss with a sharp movement so as to cause to turn over in the air
• noun a sudden muscle spasm; especially one caused by a nervous condition
• verb move or pull with a sudden motion
• verb move with abrupt, seemingly uncontrolled motions
• verb squeeze tightly between the fingers
• verb make an uncontrolled, short, jerky motion