Gossamer
Middle English: apparently from goose + summer1, perhaps from the time of year around St Martin's summer, i.e. early November, when geese were eaten (gossamer being common then).
wiktionary
From Middle English gossomer, gosesomer, gossummer (attested since around 1300, and only in reference to webs or other light things), usually thought to derive from gos(“goose”) + somer(“summer”) [1] and to have initially referred to a period of warm weather in late autumn when geese were eaten [2] [3] [4] [5] — compare Middle Scots goesomer, goe-summer(“summery weather in late autumn; St Martin's summer”) [1] and dialectal English go-harvest, [6] both later connected in folk-etymology to go) [5] [7] [8] — and to have been transferred to cobwebs because they were frequent then or because they were likened to goose- down. [2] [3] [5] [4] Skeat says that in Craven the webs were called summer-goose, and compares Scots and dialectal English use of summer-colt in reference to "exhalations seen rising from the ground in hot weather". [9] Weekley notes that both the webs and the weather have fantastical names in most European languages: [10] compare German Altweibersommer(“Indian summer; cobwebs, gossamer”, literally “ old wives' summer”) and other terms listed there.
etymonline
gossamer (n.)
c. 1300, "filmy substance (actually spider threads) found in fields of stubble in late fall," apparently from gos "goose" (see goose (n.)) + sumer "summer" (see summer (n.)). Not found in Old English. The reference might be to a fancied resemblance of the silk to goose down, or more likely it is shifted from an original sense of "late fall; Indian summer" because geese are in season then. Compare Swedish equivalent sommartrad "summer thread," Dutch zommerdraden (plural). The German equivalent mädchensommer (literally "girls' summer") also has a sense of "Indian summer," and there was a Scottish go-summer "period of summer-like weather in late autumn" (1640s, folk-etymologized as if from go). Thus the English word originally might have referred to a warm spell in autumn before being transferred to a phenomenon especially noticeable then. Compare obsolete Scottish go-summer "period of summer-like weather in late autumn." Meaning "anything light or flimsy" is from c. 1400; as a type of gauze used for veils, 1837. The adjective sense "filmy, light as gossamer" is attested from 1802.
