黒こく点てん

noun

black spot; dark spot

General term for a dark or black spot on a surface, such as a stain, blemish, or marking.

• 壁かべに黒こく点てんがついている。

  There is a black spot on the wall.

noun

sunspot

Astronomical term for a temporary dark patch on the sun's surface.

• 太たい陽ようの黒こく点てんは約やく11年ねん周しゅう期きで増ぞう減げんする。

  Sunspots increase and decrease in an approximately 11-year cycle.