left-side kata radical (no. 90)
爿 is a radical form used on the left side of characters, historically representing a bed or a split piece of wood. Its standalone meaning is tied to this radical role rather than a common independent word.
爿 is the left-side form of the radical derived from a pictograph of a bed or a split piece of wood. It is used as a component in characters related to beds, planks, or splitting.
Picture a wooden bed frame turned on its side, with the two horizontal strokes as the headboard and footboard, and the vertical stroke as the side rail. 爿 is the left-side bed radical.
For ショウ, imagine a short bed that only fits a child: short -> ショウ, and the bed radical 爿 is short like a child's bed.