Gossamer

What we call Indian summer - the spell of fine weather in late fall - was in England called goose summer (Middle English gossomer); it was the season for eating the fatted goose. But in that season, fine spider-webs might glisten of a pleasant morn. In German sommer is used both of the season and of "summer-film"; whence gossamer is applied to any very thin or delicate material. It was once guessed that the word came from God-summer; compare to the history of goodbye. It is also suggested that the word is from God's seam, or thread, that as legend tells this filmy substance is the ravelling of the winding-sheet of the Virgin Mary, which trailed back to earth as she ascended to heaven. And mention is made, too, of the Latin gossipin - cotton. Enough to break the gossamer thread.

- From Joseph Shipley's Dictionary of Word Origins