正せい中ちゅう線せん

noun

median line; midline

Used in anatomy, geometry, and technical contexts to refer to a line that divides something into left and right halves.

• 人じん体たいの正せい中ちゅう線せんは、左さ右ゆう対たい称しょうの基き準じゅんとなる。

  The body's median line serves as a reference for bilateral symmetry.

• この図ず形けいの正せい中ちゅう線せんを引ひいてください。

  Please draw the midline of this figure.