Refers to the area or direction to the left of something. Often used in spatial descriptions.
There is a bookshelf on the left side of the desk.
A car came from the left side.
horizontal left-to-right writing
Compound of 左 (ひだり, 'left') and 横 (よこ, 'side'). The exact historical derivation is uncertain, but the meaning is transparent from its components.