裏
うら · ura · JLPT N4 · noun
side
👕 裏 = 衣 (clothing) split open around 里: the lining, the inside face
The character is 衣 (garment) pulled apart, top and bottom, with 里 (ri, the sound part) tucked inside. It originally meant a garment's lining, the side that faces inward, and widened to the back or reverse side of anything. Opposite of 表 (omote), the front.