An Etymological Dictionary of Astronomy and Astrophysics

1. To spread over an area or surface.
   

2. Something that covers.

Etymology (EN): From M.E., from O.Fr. covrir, from L. cooperire “to cover over, overwhelm, bury,” from the intensive prefix → com- + operire “to close, cover.”

Etymology (PE): Pušidan “to cover; to put on,” → envelope; pušeš, verbal noun of
pušidan.