n. In anatomy, a little rod or rod-like body, as one of the rods of the retina.n. An individual of the genus Bacillus.n. [capitalized] A so-called genus of the microscopical vegetable organisms known as bacteria, having the form of very slender straight filaments, short or of moderate length, and consisting of one or more elongated cylindrical joints.n. [capitalized] In entomology, a genus of orthopterous gressorial insects, of the family Phasmidæ, the walking-sticks.n. Medicine made up into a long round figure like a stick.n. In sponges, a microstrongyle; a form of spicule.