n. In zoöl. and anat.:n. A spine, in any sense.n. The Spine, or spinal column; the backbone: more fully called spina dorsalis or spina dorsi, also columna spinalis.n. In ornithology, a genus of fringilline birds, the type of which is S. lesbia of southern Europe. Kaup, 1829. Also called Buscarla. See Spinus.n. In Roman antiquity, a barrier dividing the hippodrome longitudinally, about which the racers turned.n. One of the quills of a spinet or similar instrument.n. A slender projection from the upper, median portion of a bird's sternum, just between the articulations of the coracoids.