noun
interior angle; internal angle
Mathematical term for the angle inside a polygon or between two lines.
See also: 外角
三角形の内角の和は180度です。
The sum of the interior angles of a triangle is 180 degrees.
noun
inside corner
Baseball term for a pitch thrown on the inside part of the strike zone, close to the batter.
See also: 外角
ピッチャーは内角を厳しく攻めた。
The pitcher aggressively attacked the inside corner.