(1):

(n.) Any one of numerous species of singing birds belonging to Turdus and allied genera. They are noted for the sweetness of their songs.

(2):

(n.) An affection of the mouth, fauces, etc., common in newly born children, characterized by minute ulcers called aphthae. See Aphthae.

(3):

(n.) An inflammatory and suppurative affection of the feet in certain animals. In the horse it is in the frog.

(4):

(n.) 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.