The Collaborative International Dictionary of English v.0.48:

enveloping \enveloping\ adj.
   1. surrounding closely on all sides.

   Syn: ambient, encompassing, surrounding(prenominal).
        [WordNet 1.5 +PJC]

The Collaborative International Dictionary of English v.0.48:

enveloping \enveloping\ n.
   the act or process of enclosing something inside something
   else.

   Syn: enclosure, enclosing, envelopment, inclosure.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Envelop \En*vel"op\, v. t. [imp. & p. p. Enveloped; p. pr. &
   vb. n. Enveloping.] [OE. envolupen, envolipen, OF.
   envoluper, envoleper, F. envelopper; pref. en- (L. in) +
   voluper, voleper. See Develop.]
   To put a covering about; to wrap up or in; to inclose within
   a case, wrapper, integument or the like; to surround
   entirely; as, to envelop goods or a letter; the fog envelops
   a ship.
   [1913 Webster]

         Nocturnal shades this world envelop.     --J. Philips.
   Envelope

WordNet (r) 3.0 (2006):

enveloping
    adj 1: surrounding and closing in on or hemming in; "the army's
           enveloping maneuver"