E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
properly means a gnat curtain. Herodotus tells us (ii. 95) that the fishermen of the Nile used to lift their nets on a pole, and form thereby a rude sort of tent under which they slept securely, as gnats will not pass through the meshes of a net. Subsequently the tester of a bed was so called, and lastly the canopy borne over kings. (Greek, , a gnat; εo a gnat-curtain; Latin, conpum, a gnatcurtain.)