ellipse

Where does the word "ellipse" come from? It comes from Greek elleipsis, and was adopted directly into English (1753).

Ellipse’s story begins in Greek: elleipsis meant “a falling short, a deficiency.” Literally a falling short, describing a curve where a cone's slice falls short of a full circle. It reached English by 1753 as ellipse. Greek 'falling short'; Kepler showed in 1609 that planets move in ellipses. Today, ellipse means a regular oval shape, mathematically defined as a curve resembling a flattened circle.

1. Stage 1 · Greek · ancient elleipsis "a falling short, a deficiency", literally a falling short, describing a curve where a cone's slice falls short of a full circle.
2. Stage 2 · English · 1753 ellipse "an oval curved shape", Greek 'falling short'; Kepler showed in 1609 that planets move in ellipses.