goose (n.)

type of thorny shrub with hairy fruit, cultivated in northern Europe, 1530s, with berry, but the first part is of uncertain origin; no part of the plant seems to suggest a goose. Watkins points to Old French grosele "gooseberry," which is from Germanic. Or perhaps from German Krausebeere or Kräuselbeere, related to Middle Dutch croesel "gooseberry," and to German kraus "crispy, curly" [Klein, etc.]. By either path it could be related to the Germanic group of words in kr-/cr- and meaning "to bend, curl; bent, crooked; rounded mass." Under this theory, gooseberry would be folk etymology. But OED editors find no reason to prefer this to a literal reading, because "the grounds on which plants and fruits have received names associating them with animals are so commonly inexplicable, that the want of appropriateness in the meaning affords no sufficient ground for assuming that the word is an etymological corruption."

As slang for a fool, 1719, perhaps an extended form of goose (n.) in this sense, or a play on gooseberry fool in the cookery sense. Gooseberry also meant "a chaperon" (1837) and "a marvelous tale." Old Gooseberry for "the Devil" is recorded from 1796. In euphemistic explanations of reproduction to children, babies sometimes were said to be found under a gooseberry bush.

Middle English toth "human or animal tooth," from Old English toð (plural teð), from Proto-Germanic *tanthu- (source also of Old Saxon, Danish, Swedish, Dutch tand, Old Norse tönn, Old Frisian toth, Old High German zand, German Zahn, Gothic tunþus), from PIE root *dent- "tooth."

Plural teeth is an instance of i-mutation. The loss of -n- before spirants is regular in Old English, Old Frisian, and Old Saxon: compare goose (n.), five, mouth (n.). Also thought, from stem of think; couth from the stem of can (v.1); us from *uns.

As "appetite, bodily desire" from late 14c. (as in colt's tooth, sweet tooth, dry tooth "thirst," toothsome, and compare figurative use of palate). Application to tooth-like parts (of saws, combs, etc.) is from late 14c.

Tooth and nail "with biting and scratching, with nails and teeth," hence "viciously, furiously" is from early 14c. (as nayles and teþ). To be armed to the teeth is from c. 1300. The tooth-fairy is attested from 1964.