semiminor axis

American  

[sem-ee-mahy-ner, sem-ahy-, sem-ee-, sem-ahy-] / ˈsɛm iˈmaɪ nər, ˈsɛm aɪ-, ˌsɛm i-, ˌsɛm aɪ- /

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.

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Etymology

Origin of semiminor axis

First recorded in 1925–30; semi- + minor