n. Armor for the body, in use after the perfecting of plate-armor; specifically, in the sixteenth century, the breast- and back-pieces taken together.n. The breastplate taken by itself.n. The complete armor of a pikeman, musketeer, etc., consisting of breast and back, gauntlets and tassets, with a morion or open headpiece.n. In zoology: In entomology, the thorax of an insect; that part to which the wings and legs are attached.n. In ichthyology, a zone or area of scales, larger than the rest, developed behind the head and about the pectoral fins of certain scombroid fishes, as in the tunnies, albicores, bonitos, and frigate-mackerels.n. In conchology, a ridge in the hinge of bivalves with an external ligament, with which the ligament is connected.To encircle with or as with a corselet.