redline

noun

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.

verb

1. To mark a drawing or document for correction or modification.
2. To operate a device at one or more redlines.
3. To operate a device at one or more redlines.
4. (Canada, US)To deny or complicate access to services (such as banking, insurance, or healthcare) to residents in specific, often racially determined, areas.

   “Already ‘redlined’ by profit-hungry telcos, the inhabitants of poor inner city areas can be shut out of the new on-line services through lack of money.”

5. To achieve audio levels that will cause clipping (indicated by red in an audio meter).