1. a sheet or layer of rock that has been moved far from its original position by tectonic forces
Usage: geology
2. a sheet of water flowing over a weir or dam
Usage: engineering; hydraulics
3. either of the two parts of a cone on opposite sides of the vertex
Usage: mathematics; geometry

Examples

• The Alpine nappe was thrust over younger rocks during mountain formation.
• Geologists studied the nappe structure to understand the region's tectonic history.
• Water flowed over the dam in a thin nappe before falling into the pool below.
• The cone's upper nappe extends upward from the vertex.
• A double nappe forms when a plane intersects both parts of a cone.