The Collaborative International Dictionary of English v.0.48:

Siren \Si"ren\, n. [L., fr. Gr. ???: cf. F. sir[`e]ne.]
   1. (Class. Myth.) One of three sea nymphs, -- or, according
      to some writers, of two, -- said to frequent an island
      near the coast of Italy, and to sing with such sweetness
      that they lured mariners to destruction.
      [1913 Webster]

            Next where the sirens dwell you plow the seas;
            Their song is death, and makes destruction please.
                                                  --Pope.
      [1913 Webster]

   2. An enticing, dangerous woman. --Shak.
      [1913 Webster]

   3. Something which is insidious or deceptive.
      [1913 Webster]

            Consumption is a siren.               --W. Irving.
      [1913 Webster]

   4. A mermaid. [Obs.] --Shak.
      [1913 Webster]

   5. (Zool.) Any long, slender amphibian of the genus Siren
      or family Sirenidae, 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.
      [1913 Webster]

   6. [F. sir[`e]ne, 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.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Siren \Si"ren\, a.
   Of or pertaining to a siren; bewitching, like a siren;
   fascinating; alluring; as, a siren song.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Siren
    n 1: a sea nymph (part woman and part bird) supposed to lure
         sailors to destruction on the rocks where the nymphs lived;
         "Odysseus ordered his crew to plug their ears so they would
         not hear the Siren's fatal song"
    2: a woman who is considered to be dangerously seductive [syn:
       enchantress, temptress, siren, Delilah, femme
       fatale]
    3: a warning signal that is a loud wailing sound
    4: an acoustic device producing a loud often wailing sound as a
       signal or warning
    5: eellike aquatic North American salamander with small
       forelimbs and no hind limbs; have permanent external gills

Moby Thesaurus II by Grady Ward, 1.0:

200 Moby Thesaurus words for "siren":
   Circe, Davy, Davy Jones, Don Juan, Dylan, Euryale, Gorgon, Jezebel,
   Klaxon, Lorelei, Mayday, Medea, Medusa, Neptune, Nereid, Nereus,
   Oceanid, Oceanus, Parthenope, Poseidon, SOS, Siren, Stheno, Thetis,
   Triton, Varuna, air-raid alarm, alarm, alarm bell, alarm clock,
   alarm signal, alarum, alert, all clear, alluring, appealing,
   appetizing, attracting, attractive, beacon, beguiling, beldam,
   bewitcher, bewitching, bitch-kitty, blandishing, blinking light,
   boiler factory, boiler room, bull-roarer, burglar alarm, buzzer,
   cajoling, captivating, catcall, catching, charismatic, charmer,
   charming, cherry bomb, clack, clacker, clapper, coaxing,
   come-hither, coquette, coquettish, cracker, cricket, crostarie,
   drawing, enchanter, enchanting, enchantress, engaging, enravishing,
   enthralling, enticer, enticing, entrancing, exciting, exotic,
   fascinating, femme fatale, fetching, fiery cross, fire alarm,
   fire bell, fire flag, firecracker, five-minute gun, flashing light,
   flirt, flirtatious, fog bell, fog signal, foghorn,
   fresh-water nymph, fury, gale warning, glamorous, grimalkin, hag,
   hellcat, hellhag, hooter, horn, hue and cry, hurricane warning,
   hypnotic, interesting, intriguing, inveigler, inviting,
   irresistible, kelpie, lighthouse, limniad, magnetic, man fish,
   mermaid, merman, mesmeric, mouth-watering, naiad, nix, nixie,
   noisemaker, note of alarm, occulting light, ocean nymph, piquant,
   police whistle, prepossessing, provocative, provoquant, rattle,
   rattlebox, ravishing, sea devil, sea god, sea nymph, sea-maid,
   sea-maiden, seaman, seducer, seducing, seductive, seductress,
   she-devil, she-wolf, signal, signal of distress, sirenic,
   small-craft warning, snapper, sorceress, spellbinder, spellbinding,
   spellful, steam whistle, still alarm, storm cone, storm flag,
   storm warning, taking, tantalizing, teaser, teasing, tempter,
   tempting, temptress, termagant, tickling, ticktack, tigress,
   titillating, titillative, tocsin, two-minute gun, undine,
   upside-down flag, vamp, vampire, virago, vixen, wailer, warble,
   warning, water god, water spirit, water sprite, whistle, whizgig,
   whizzer, wildcat, winning, winsome, witch, witching



The Devil's Dictionary (1881-1906):

SIREN, n.  One of several musical prodigies famous for a vain attempt
to dissuade Odysseus from a life on the ocean wave.  Figuratively, any
lady of splendid promise, dissembled purpose and disappointing
performance.


U.S. Gazetteer Places (2000):

Siren, WI -- U.S. village in Wisconsin
   Population (2000):    988
   Housing Units (2000): 499
   Land area (2000):     1.103843 sq. miles (2.858940 sq. km)
   Water area (2000):    0.022314 sq. miles (0.057793 sq. km)
   Total area (2000):    1.126157 sq. miles (2.916733 sq. km)
   FIPS code:            74175
   Located within:       Wisconsin (WI), FIPS 55
   Location:             45.783633 N, 92.380161 W
   ZIP Codes (1990):     54872
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Siren, WI
    Siren