Rattlebox \Rat"tle*box`\, n. 1. A toy that makes a rattle sound; a rattle. 2. (Bot.) (a) An American herb ({Crotalaria sagittalis}), the seeds of which, when ripe, rattle in the inflated pod. (b) Any species of {Crotalaria}, a genus of yellow-flowered herbs, with inflated, many-seeded pods.