長ちょう半はん径けい

noun

semi-major axis

Geometry term for half the longest diameter of an ellipse. Also called 半長径.

See also: 半長径

• 楕だ円えんの長ちょう半はん径けいは、中ちゅう心しんから最もっとも遠とおい点てんまでの距きょ離りです。

  The semi-major axis of an ellipse is the distance from the center to the farthest point.