segment

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

• noun Any of the parts into which something can be divided.
• noun The portion of a line between any two points on the line.
• noun The area bounded by a chord and the arc of a curve subtended by the chord.
• noun The portion of a sphere cut off by two parallel planes.
• noun Biology A clearly differentiated subdivision of an organism or part, such as a metamere.
• transitive & intransitive verb To divide or become divided into segments.

from The Century Dictionary.

• noun An element of a machine, such as a toothed wheel, cam, or pulley, the active surface of which is not a full surface of revolution, but only a segment or part of such surface.
• noun A part cut off or marked as separate from others; one of the parts into which a body naturally divides itself; a section: as, the segments of a calyx; the segments of an orange; the segments of a leaf.
• noun In geometry, a part cut off from any figure by a line or plane.
• noun In heraldry, a bearing representing one part only of a rounded object, as a coronet or wreath: usually a piece less than half of the circle.
• To divide or become divided or split up into segments.
• To separate or divide into segments: as, a segmented cell.

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

• intransitive verb (Biol.) To divide or separate into parts in growth; to undergo segmentation, or cleavage, as in the segmentation of the ovum.
• noun One of the parts into which any body naturally separates or is divided; a part divided or cut off; a section; a portion
• noun (Geom.) A part cut off from a figure by a line or plane; especially, that part of a circle contained between a chord and an arc of that circle, or so much of the circle as is cut off by the chord.
• noun A piece in the form of the sector of a circle, or part of a ring.
• noun A segment gear.
• noun One of the cells or division formed by segmentation, as in egg cleavage or in fissiparous cell formation.
• noun One of the divisions, rings, or joints into which many animal bodies are divided; a somite; a metamere; a somatome.
• noun a piece for receiving or communicating reciprocating motion from or to a cogwheel, consisting of a sector of a circular gear, or ring, having cogs on the periphery, or face.
• noun the part of a line contained between two points on it.
• noun the part of a sphere cut off by a plane, or included between two parallel planes.
• noun (Acoustics) See Loor, n., 5.

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

• noun A length of some object.
• noun mathematics A straight path between two points that is the shortest distance between them.
• noun geometry The part of a circle between its circumference and a chord (usually other than the diameter).
• noun topology Any of the pieces that comprise an order tree.
• noun phonology A consonant or a vowel.
• noun broadcasting A part of a broadcast program, devoted to a topic.
• noun computing An Ethernet bus.
• noun travel A portion of an itinerary; can be a flight or train between two cities, a car or hotel booked in a particular city.
• noun botany A portion of an organ whose cells are derive from a single cell within the primordium from which the organ developed.
• noun zoology One of several parts of an organism, with similar structure, arranged in a chain; such as a vertebra, or a third of an insect's thorax.
• verb To divide into segments or sections.

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

• verb divide or split up
• verb divide into segments
• noun one of the parts into which something naturally divides
• noun one of several parts or pieces that fit with others to constitute a whole object