semiminor axis

[ sem-ee-mahy-ner, sem-ahy-, sem-ee-, sem-ahy- ]

noun

1. Geometry. one half the minor axis of an ellipse.
2. Astronomy. one half the minor axis of the ellipse that one celestial body describes around another, as a planet around the sun.

Word History and Origins

Origin of semiminor axis¹

First recorded in 1925–30; semi- + minor