1. Greek mythology: any of a group of sea nymphs (often portrayed as half human and half bird, and to a lesser extent, half human and half fish that lured mariners to destruction by their singing.
2. a woman regarded as seductive and beautiful, especially a dangerous woman; temptress.
3. a woman who sings with enchanting sweetness.
4. a) a device in which compressed air or steam is driven against a rotating perforated disk to create a loud, often wailing sound as a signal or warning. b) an electronic device producing a similar sound as a signal or warning.
5. any of several salamanders of the family Sirenidae, such as the mud eel, having an eellike body, permanent external gills, small forelegs, and no hind limbs.
Etymology: from Old French sereine, from Latin sīrēn, from Greek seirēn.