Originally: any animal of the group Sipuncula; = "sipunculan". In later use chiefly as the genus name Sipunculus.
Early 19th century; earliest use found in Universal System of Natural History. From scientific Latin Sipunculus, genus name (Linnaeus Systema Naturae (ed. 12, 1766) I. ii. 1078) from classical Latin sīpunculus, variant of sīphunculus.