Word Study
nappe
CIDE DICTIONARY
nappe, n. [F. nappe cloth, sheet. See Napery.].
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. [1913 Webster]
OXFORD DICTIONARY
nappe, n. Geol. a sheet of rock that has moved sideways over neighbouring strata, usu. as a result of overthrust.
Etymology
F nappe tablecloth
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