黒こく線せん

noun

black line

General term for a black-colored line, used in everyday contexts such as drawing, design, or markings.

• 地ち図ずに黒こく線せんを引ひいてルートを示しめした。

  I drew a black line on the map to show the route.

noun

linea nigra; pregnancy line

Medical term for the dark vertical line that appears on the abdomen during pregnancy.

• 妊にん娠しん中ちゅうに現あらわれる黒こく線せんは、ホルモンの変へん化かによるものです。

  The linea nigra that appears during pregnancy is due to hormonal changes.