Envelop

a. [Fr. envelop per, from Lat. involve rein, and volvere, to roll; L. Lat. in vol pare. See VOLUBLE.] To roll or fold in; to infold; to cover by wrapping and folding; to inwrap; as, to envelop a letter. - To cover on all sides; to hide; to surround entirely; as, envel oped in fog. "A cloud of smoke envelops either host." - Dryden . En'velope, Envelop, n . That which infolds or inwraps; a wrapper; a cover; a covering for a letter, parcel, .; an investing integument; an outward covering or case. (Astron.) Same as COMA, q . v. (Portif.) An earthwork raised to defend a weaker one. (Geom.) Curve or surface generated by the repeated interjections of given curves or surfaces, whose position, form, and magnitude are allowed to vary according to some continuous law.