1. Classical Mythology. one of several sea nymphs, part woman and part bird, who lure mariners to destruction by their seductive singing.
2. a seductively beautiful or charming woman, especially one who beguiles men:
a siren of the silver screen.
3. an acoustical instrument for producing musical tones, consisting essentially of a disk pierced with holes arranged equidistantly in a circle, rotated over a jet or stream of compressed air, steam, or the like, so that the stream is alternately interrupted and allowed to pass.
4. an implement of this kind used as a whistle, fog signal, or warning device.