obvŏlūtĭo — Lewis & Short
obvŏlūtĭo, ōnis, f.obvolvo,
I a wrapping round, enveloping; an envelope (postclass.):
aetherea obvolutio,Macr. Somn. Scip. 1, 11, § 12; Cael. Aur. Acut. 2, 11, 79.