noun
angle of inclination; tilt angle
Technical term used in geometry, engineering, and physics to describe the angle between a line or plane and a reference plane, typically the horizontal.
この斜面の傾斜角は約30度です。
The angle of inclination of this slope is about 30 degrees.
傾斜角が急すぎると、車両が登れなくなる。
If the tilt angle is too steep, vehicles cannot climb it.
角度 is a general term for any angle, whereas 傾斜角 is specifically the angle of inclination or tilt.
Compound of 傾斜 (keisha, 'inclination, slope') and 角 (kaku, 'angle'). The reading is the standard on'yomi for each kanji.