noun
plane mirror
A flat mirror that reflects light without distortion; used in physics and everyday contexts.
平面鏡に映った像は左右が逆になる。
The image reflected in a plane mirror is reversed left to right.
Concave mirror; 平面鏡 is flat, while 凹面鏡 curves inward.
Convex mirror; 平面鏡 is flat, while 凸面鏡 curves outward.
Compound of 平面 (flat surface) and 鏡 (mirror).