noun
key plate (printing)
In printing, the plate that carries the most detail, usually the black plate, used as a guide for registering other colors.
カラー印刷では、キープレートを基準に他の色を合わせます。
In color printing, other colors are aligned based on the key plate.
noun
key tag; label holder for a key ring
A small plastic or metal tag attached to a key ring, often used to write the key's purpose or room number.
合鍵にキープレートを付けて、どこの鍵かわかるようにした。
I attached a key tag to the spare key so I can tell which key it is.