What does "siren" mean?

Additional senses

1. 2.Something which is insidious or deceptive. Consumption is a siren. W. Irving.
2. 3.A mermaid. [Obs.] Shak.
3. 4.(Zoöl.) Any long, slender amphibian of the genus Siren or family Sirenidæ, destitute of hind legs and pelvis, and having permanent external gills as well as lungs. They inhabit the swamps, lagoons, and ditches of the Southern United States. The more common species (Siren lacertina) is dull lead-gray in color, and becames two feet long.
4. 5.Etym: [F. sirène, properly, a siren in sense 1.] (Acoustics) An instrument for producing musical tones and for ascertaining the number of sound waves or vibrations per second which produce a note of a given pitch. The sounds are produced by a perforated rotating disk or disks. A form with two disks operated by steam or highly compressed air is used sounding an alarm to vessels in fog. [Written also sirene, and syren.]
5. 6.Of or pertaining to a siren; bewitching, like a siren; fascinating; alluring; as, a siren song.