PIE*ghans、ガチョウ、語源的にはgannet、ganderと同じ。
Geese are technically distinguished from swans and from ducks by the combination of feathered lores, reticulate tarsi, stout bill high at the base, and simple hind toe. [Century Dictionary]Spanish ganso "goose" is from a Germanic source. Loss of "n" sound is normal before "s." Plural form geese is an example of i-mutation. Meaning "simpleton, silly or foolish person" is from early 15c. To cook one's goose first attested 1845, of unknown origin; attempts to connect it to Swedish history and Greek fables are unconvincing. Goose-egg "zero" first attested 1866 in baseball slang, from being large and round. The goose that lays golden eggs (15c.) is from Aesop.