redline

To mark a drawing or document for correction or modification.

To operate a device at one or more redlines.

(automotive) To run an internal combustion engine to its maximum or maximum recommended speed.

(Canada, US, urban studies) To deny or complicate access to services (such as banking, insurance, or healthcare) to residents in specific, often racially determined, areas.

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