Nappe

1. n. Sheet; surface; all that portion of a surface that is continuous in such a way that it is possible to pass from any one point of the portion to any other point of the portion without leaving the surface. Thus, some hyperboloids have one nappe, and some have two.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.