Real Dictionary

thrush
countable noun: A thrush is a fairly small bird with a brown back and a spotted breast.
uncountable noun: Thrush is a medical condition caused by a fungus. It most often occurs in a baby's mouth or in a woman's vagina.

thrush in American English 1
noun: any of numerous, medium-sized songbirds of the family Turdinae, usually dull brown and often speckled below, and including many outstanding singers

thrush in American English 2
noun: a disease, esp. in children, characterized by whitish spots and ulcers on the membranes of the mouth, fauces, etc., caused by a parasitic fungus Candida albicans

thrush in British English 1
noun: any songbird of the subfamily Turdinae, esp those having a brown plumage with a spotted breast, such as the mistle thrush and song thrush: family Muscicapidae

thrush in British English 2
noun: a fungal disease of the mouth, esp of infants, and the genitals, characterized by the formation of whitish spots and caused by infection with the fungus Candida albicans