nappe

UK: /næp/ US: (nap)

WordReference Random House Unabridged Dictionary of American English © 2026

nappe  (nap), n. 

1. Geology a large mass of rock thrust a considerable distance along a nearly horizontal fault plane or in an overturned anticlinal fold.
2. Mathematics [Geom.] one of the two equal sections of a cone.

• Latin mappa; compare napkin
• French: literally, tablecloth, cloth; Old French nappe, nape
• 1905–10, American.

Collins Concise English Dictionary © HarperCollins Publishers::

nappe / næp/ noun

1. a large sheet or mass of rock, commonly a recumbent fold, that has been thrust from its original position by earth movements
2. the sheet of water that flows over a dam or weir
3. either of the two parts into which a cone (sense 2) is divided by the vertex

Etymology: 20th Century: from French: tablecloth