Definition:Cone/Double Napped Cone/Nappe

Definition

Each of the halves of a double napped cone is a nappe.

Also known as

Some sources use the term sheet rather than nappe.

Linguistic Note

The word nappe is of French origin and means layer or sheet.

Sources

• 1933: D.M.Y. Sommerville: Analytical Conics (3rd ed.) ... (previous) ... (next): Chapter $\text {IV}$. The Ellipse: $1$.
• 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): nappe
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): nappe
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): nappe

• Weisstein, Eric W. "Nappe." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Nappe.html