square plate; rectangular dish
Refers to a plate or dish with a square or rectangular shape, as opposed to a round one.
When you arrange food on a square plate, it gives a sharper appearance.
Compound of 角 (kaku, 'angle' or 'square') and 皿 (sara, 'plate'). The reading かくざら is a straightforward combination of the on'yomi of 角 and the kun'yomi of 皿.