envelop

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To enclose or encase completely with or as if with a covering: "Accompanying the darkness, a stillness envelops the city” ( Curtis Wilkie).
2. v. To attack (an enemy's flank).

Century Dictionary and Cyclopedia

1. To cover, as by wrapping or folding; inwrap; invest with or as with a covering; surround entirely; cover on all sides.
2. To form a covering about; lie around and conceal.
3. To line; cover on the inside.
4. Synonyms To encircle, encompass, infold, wrap up.
5. n. A wrapper; an inclosing cover; an integument: as, the envelop of a seed. Specifically
6. n. A prepared wrapper for a letter or other paper, so made that it can be sealed.
7. n. In fortification, a work of earth in form of parapet, or of a small rampart with a parapet, raised to cover some weak part of the works.
8. n. In astronomy, a shell partly surrounding the nucleus of a comet on the side next the sun and away from the tail, and appearing like a semicircular arch. Large comets generally show several of these under the telescope. They successively rise from the nucleus and disappear.
9. n. In geometry, a curve or surface touching a continuous series of curves or surfaces. Thus, suppose a plane curve to undergo a continuous change in its shape and position; then the curve as it is at any instant is intersected by the curve as it is at any subsequent instant, and the closer the second instant follows after the first the closer do these intersections approach certain positions on the first curve. These positions are points on the envelop, and in this way all the points on the envelop are determined. If t is a variable parameter, and P = 0 is the equation of the surface, then the equation obtained by eliminating t between P = 0 and dP/dt = 0 is the equation to the envelop. Or if there are two variable parameters, s and t, the equation of the envelop is obtained by eliminating them between P = 0, dP/ds = 0, and dP/dt = 0. Every curve may thus be regarded as an envelop. Caustics, evolutes, etc., are so by their definitions.

Wiktionary

1. v. transitive To surround or enclose.

GNU Webster's 1913

1. v. To put a covering about; to wrap up or in; to inclose within a case, wrapper, integument or the like; to surround entirely

WordNet 3.0

1. v. enclose or enfold completely with or as if with a covering