Keylines

Part of speech: noun, verb

Definitions

1. Lines that define a boundary or outline, particularly in artistic and design contexts
2. guidelines used to assist in the composition of visual elements
3. or specifications indicating critical features in technical drawings or plans

Etymology: "Keylines" is the plural of "keyline," a noun formed by combining "key" and "line." In the sense relevant here, a keyline is a guiding line drawn to mark the position of an element in a layout, such as the boundary of an image or a block of text, so that the pieces of a design can be placed accurately. Its meaning rests on the older sense of "key" as something that opens or determines a matter, which is also why "key" can mean central or essential. The verb use, "to keyline," works the same way: to draw such guidelines onto a design or artwork. Because the word is a plain compound of two English words, its history is simple. Its parts are transparent, and its specialised sense comes from the working practice of graphic design rather than from any separate older term.