silver ratio
Mathematical term for the ratio 1:√2, used in paper sizes and design. Also known as the silver mean or silver constant.
白銀比は、A判やB判の紙の縦横比として知られている。
The silver ratio is known as the aspect ratio of A-series and B-series paper.
From 白銀 (silver) + 比 (ratio). The term is a direct calque of the English 'silver ratio', referring to the metallic mean analogous to the golden ratio.