[Not known in either sense before the 17th c., though the phonology of the word, with þ and sh, indicates English origin, and points to an OE. *þrusc. The only continental cognates appear to be, in sense 1, Sw. and ODa. tørsk, Da. troske, Sw. dial. trosk, which Falk and Torp refer to an ON. *þruskr. See Note below.]
1. A disease, chiefly of infants, characterized by white vesicular specks on the inside of the mouth and throat, and on the lips and tongue, caused by a parasitic fungus (see thrush-fungus in 3); scientifically called aphtha or parasitic stomatitis.
1665. Pepys, Diary, 17 June. He hath a fever, a thrush and a hickup.
1712. trans. Pomet’s Hist. Drugs, I. 47. A Gargle of it cures the Thrush.
1828. Mrs. Bray, Protestant, xvii. (1884), 180. The thrush, colic, and other disorders incidental to children.
1877. Roberts, Handbk. Med. (ed. 3), I. 289. Thrush is frequently associated with typhoid fever.
2. In the horse, An inflammation of the lower surface of the frog of the hoof, accompanied with a fetid discharge. Cf. FRUSH sb.2
1753. J. Bartlet, Gentl. Farriery (1754), 319. Of the Running Thrush. Bathe the thrush with this, wherever there appears a more than ordinary moisture, and lay over the ulcer a little tow dipped in the same.
1810. Sporting Mag., XXXVI. 154. It had a thrush, spavins and contracted knees.
1831. [Youatt], Horse, xvi. 307. Thrush is a discharge of offensive matter from the cleft of the frog. It is inflammation of the lower surface of the sensible frog.
3. Comb.: thrush-fungus, the parasitic fungus Saccharomyces albicans, which causes thrush (sense 1); thrush-lichen, thrush-moss, a species of lichen, Peltigera aphthosa, found on moist alpine rocks, and used in Sweden boiled in milk as a cure for thrush (sense 1); thrush-paste, an astringent paste for curing thrash in horses (sense 2).
1759. Stillingfl., Misc. Tracts (1775), 217. The countrey people taught us the virtues of the thrush-moss for sore throats.
1858. Simmonds, Dict. Trade, Thrush Lichen, the Pellidea apthosa.
1888. Cassell’s Encycl. Dict., Thrush-lichen…. Thrush-paste.
1899. Cagney, trans. Jaksch’s Clin. Diagn., iii. (ed. 4), 113. In a few cases, thrush-fungus and vegetations have been found in the nose.
[Note. Norw. has frøsk, frosk ‘thrush,’ phonetically identical with frosk frog; cf. Norw. dial. trausk = frausk, ‘frog,’ which seems to rest upon an old phonetic confusion of *þruskr and froskr. Some would connect this with the fact that Gr. βάτραχος and L. rāna, rānula, ‘frog,’ were also names of a disease in the mouth of cattle. The evidence of Eng. is however that *þrosc = *ON. þruskr, was the orig. word for the disease in sense 1. The connection of sense 2 is not explained; can it be connected with Da. trøske rotten or decayed wood, ‘rottenness in the bones’?]
