NOUN (3)

1. candidiasis of the oral cavity; seen mostly in infants or debilitated adults;

2. a woman who sings popular songs;

3. songbirds characteristically having brownish upper plumage with a spotted breast;

The Collaborative International Dictionary of English v.0.48:

Frush \Frush\, n. [Cf. OE. frosch, frosk, a frog (the animal),
   G. frosch frog (the animal), also carney or lampass of
   horses. See Frog, n., 2.]
   1. (Far.) The frog of a horse's foot.
      [1913 Webster]

   2. A discharge of a fetid or ichorous matter from the frog of
      a horse's foot; -- also caled thrush.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Thrush \Thrush\, n. [OE. [thorn]rusche, AS. [thorn]rysce; akin
   to OHG. drosca, droscea, droscela, and E. throstle. Cf.
   Throstle.]
   1. (Zool.) Any one of numerous species of singing birds
      belonging to Turdus and allied genera. They are noted
      for the sweetness of their songs.
      [1913 Webster]

   Note: Among the best-known European species are the song
         thrush or throstle (Turdus musicus), the missel
         thrush (see under Missel), the European redwing, and
         the blackbird. The most important American species are
         the wood thrush (Turdus mustelinus), Wilson's thrush
         (Turdus fuscescens), the hermit thrush (see under
         Hermit), Swainson's thrush (Turdus Aliciae), and
         the migratory thrush, or American robin (see Robin).
         [1913 Webster]

   2. (Zool.) Any one of numerous species of singing birds more
      or less resembling the true thrushes in appearance or
      habits; as the thunderbird and the American brown thrush
      (or thrasher). See Brown thrush.
      [1913 Webster]

   Ant thrush. See Ant thrush, Breve, and Pitta.

   Babbling thrush, any one of numerous species of Asiatic
      timaline birds; -- called also babbler.

   Fruit thrush, any species of bulbul.

   Shrike thrush. See under Shrike.

   Stone thrush, the missel thrush; -- said to be so called
      from its marbled breast.

   Thrush nightingale. See Nightingale, 2.

   Thrush tit, any one of several species of Asiatic singing
      birds of the genus Cochoa. They are beautifully colored
      birds allied to the tits, but resembling thrushes in size
      and habits.

   Water thrush.
      (a) The European dipper.
      (b) An American warbler (Seiurus Noveboracensis).
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Thrush \Thrush\, n. [Akin to Dan. tr["o]ske, Sw. trosk; cf. Dan.
   t["o]r dry, Sw. torr, Icel. [thorn]urr, AS. [thorn]yrr, OE.
   thrust thrist, E. thrist.]
   1. (Med.) An affection of the mouth, fauces, etc., common in
      newly born children, characterized by minute ulcers called
      aphthae. See Aphthae.
      [1913 Webster]

   2. (Far.) An inflammatory and suppurative affection of the
      feet in certain animals. In the horse it is in the frog.
      [1913 Webster]

WordNet (r) 3.0 (2006):

thrush
    n 1: candidiasis of the oral cavity; seen mostly in infants or
         debilitated adults
    2: a woman who sings popular songs
    3: songbirds characteristically having brownish upper plumage
       with a spotted breast

Moby Thesaurus II by Grady Ward, 1.0:

143 Moby Thesaurus words for "thrush":
   African lethargy, Asiatic cholera, Chagres fever, German measles,
   Haverhill fever, Philomel, acute articular rheumatism, ague,
   alkali disease, amebiasis, amebic dysentery, anthrax,
   bacillary dysentery, bastard measles, black death, black fever,
   blackwater fever, breakbone fever, brucellosis, bubonic plague,
   bulbul, cachectic fever, canary, cerebral rheumatism, chicken pox,
   cholera, cowpox, cuckoo, dandy fever, deer fly fever, dengue,
   dengue fever, diphtheria, dumdum fever, dysentery, elephantiasis,
   encephalitis lethargica, enteric fever, erysipelas, famine fever,
   feathered songster, five-day fever, flu, frambesia,
   glandular fever, grippe, hansenosis, hepatitis, herpes,
   herpes simplex, herpes zoster, histoplasmosis, hookworm,
   hydrophobia, infantile paralysis, infectious mononucleosis,
   inflammatory rheumatism, influenza, jail fever, jungle rot,
   kala azar, kissing disease, lark, lepra, leprosy, leptospirosis,
   loa loa, loaiasis, lockjaw, madness, malaria, malarial fever,
   marsh fever, mavis, measles, meningitis, milzbrand, mockingbird,
   mumps, nightingale, oriole, ornithosis, osteomyelitis,
   paratyphoid fever, parotitis, parrot fever, pertussis, pneumonia,
   polio, poliomyelitis, polyarthritis rheumatism, ponos, psittacosis,
   rabbit fever, rabies, rat-bite fever, relapsing fever,
   rheumatic fever, rickettsialpox, ringdove, ringworm, rubella,
   rubeola, scarlatina, scarlet fever, schistosomiasis,
   septic sore throat, shingles, singing bird, sleeping sickness,
   sleepy sickness, smallpox, snail fever, song sparrow, songbird,
   songster, splenic fever, spotted fever, strep throat, swamp fever,
   tetanus, tinea, trench fever, trench mouth, tuberculosis,
   tularemia, typhoid, typhoid fever, typhus, typhus fever,
   undulant fever, vaccinia, varicella, variola, venereal disease,
   viral dysentery, warbler, whooping cough, yaws, yellow fever,
   yellow jack, zona, zoster