Gg: Gossamer

They have even convinced themselves that thin air is good for their bellies and following that logic, have gone on sparse diets, refuting all but the most gossamer food.

Einstine's Dreams by Alan Lightman.

Noun

1. a very fine fabric

2. a filmy cobweb often seen on foliage or floating in the air [probably Middle English gos goose + somer summer; referring to St Martin's summer, a period in November when goose was eaten and cobwebs abound]