Crawling on the belly, as a snake, or reptant, as an ophidian; of or pertaining to the Serpentia: correlated with salient and gradient.Having the form or nature of a serpent; of a kind similar to that which a serpent has or might have.Serpentine; winding; tortuous.n. A scaly creature that crawls on the belly; a limbless reptile; properly, a snake; any member of the order Ophidia (which see for technical characters).n. [capitalized] In astronomy, a constellation in the northern hemisphere. See Ophiuchus.n. A musical instrument, properly of the trumpet family, having a cupped mouthpiece, a conical wooden tube bent to and fro several times and usually covered with leather, and nine fingerholes very irregularly disposed.n. In organ-building, a reed-stop similar to the trombone.n. Figuratively, a person who in looks or ways suggests a serpent; a wily, treacherous person; rarely, a fatally fascinating person.n. A kind of firework which burns with a zigzag, serpentine motion or light.n. In firearms, same as serpentin.To wind along like a snake, as a river; take or have a serpentine course; meander.To entwine; girdle as with the coils of a serpent.