noun a segment gear.
2. segment ·noun one of the cells or division formed by segmentation, as in egg cleavage or in fissiparous cell formation.
3. segment ·noun one of the divisions, rings, or joints into which many animal bodies are divided; a somite; a metamere; a somatome.
4. segment ·vi to divide or separate into parts in growth; to undergo segmentation, or cleavage, as in the segmentation of the ovum.
5. segment ·noun a piece in the form of the sector of a circle, or part of a ring; as, the segment of a sectional fly wheel or flywheel rim.
6. segment ·noun one of the parts into which any body naturally separates or is divided; a part divided or cut off; a section; a portion; as, a segment of an orange; a segment of a compound or divided leaf.
7. segment ·noun 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; as, the segment acb in the illustration.