side

/sɑɪd/ n [C] (SURFACE)

Definition

› a surface of something that is not the top or the bottom, or a surface of a flat object: Label all four sides of the box. I painted one side of the boat green to see if we like the color. The trail leads up the side of the mountain. Please write on only one side of the paper. › A side is also a surface that is not the front or the back: There’s a scratch on the side of my new bookcase.

(Definition of side n (SURFACE) from the Cambridge Academic Content Dictionary © Cambridge University Press)