redline

Meanings

Noun

• A drawing, document, etc. that has been marked for correction or modification.
• The maximum speed at which the engine in a car or aircraft etc. is designed to operate.

Verb

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

Origin

• 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).