redline

Meanings

1. A drawing, document, etc. that has been marked for correction or modification.
2. The maximum speed, temperature, pressure, etc., at which a device (such as the engine in a car, aircraft, etc.) is designed to operate.

1. To mark a drawing or document for correction or modification.
2. To operate a device at one or more redlines.
3. To run an internal combustion engine to its maximum or maximum recommended speed.
4. To deny or complicate access to services (such as banking, insurance, or healthcare) to residents in specific, often racially determined, areas.
5. To achieve audio levels that will cause clipping (indicated by red in an audio meter).

Etymology

From red + line, originating with the frequent use of red pen or pencil to mark corrections on drawings and documents (1), and the red markings on a tachometer (2).