n. In anatomy: [L.] A rib.n. A border or side of something: specifically applied to the three borders or costæ of the human scapula or shoulder-blade—the superior or coracoid, the posterior or vertebral, and the anterior or axillary.n. A ridge on something, giving it a ribbed appearance.n. In zoöl.: In entomology: A broad, elevated longitudinal line or ridge on a surface. The anterior border of an insect's wing, extending from the base to the apex or outer angle. Hence— The space on the wing bordering the anterior margin. The costal or anterior vein.n. In conchology, the ridge or one of the ridges of a shell.n. In Actinozoa, an external vertical ridge marking the site of a septum within.n. In Crinoidea, a row of plates succeeding the inferior or basal portion of the cup.n. In botany, a rib or primary vein; a midrib or midnerve of a leaf or frond.n. In Ctenophora, one of the eight meridional rows of swimming-plates.n. In Hydrozoa, one of the protective branches which form the walls of an open basketwork inclosing the gonangia, as in the corbula of Aglaophenia.n. The ridge of the sucker of a tapeworm.