Something that's enveloping encircles, enfolds, or surrounds. An enveloping fog blankets everything, seeming to close in on the entire landscape.
Some things are literally enveloping, like your grandpa's enveloping hug or an enveloping blanket around a chilly toddler. Others are enveloping in a more figurative way, like enveloping mist that seems to surround you or an enveloping fear that overcomes you as you watch a scary movie. Enveloping comes from the Old French envoleper, "cover, fold up or wrap up," from en-, "in," and voloper, "wrap up."