n. 25B6; noun
a canvas covering : AWNING, canopy, tarpaulin, cowling, casing, housing; wrapping, wrapper, cover, envelope, sheath, sleeve, jacket, lid, top, cap.
a covering of snow : LAYER, coating, coat, carpet, blanket, overlay, topping, dusting, film, sheet, veneer, crust, skin, cloak, mantle, veil.
25B6; adjective a covering letter : ACCOMPANYING, explanatory, introductory, prefatory.