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.

Origin of semiminor axis

First recorded in 1925–30; semi- + minor
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018