Sandworm \Sand"worm`\, n. (Zo["o]l.) (a) Any one of numerous species of annelids which burrow in the sand of the seashore. (b) Any species of annelids of the genus {Sabellaria}. They construct firm tubes of agglutinated sand on rocks and shells, and are sometimes destructive to oysters. (c) The chigoe, a species of flea.