red line

American  

noun

1. Ice Hockey. a line of the color red that is parallel to and equidistant from the goal lines and divides the rink in half.

2. a limit, point, or boundary beyond which one may not go without incurring negative consequences.

   The use of chemical weapons is a red line, which, if crossed, could trigger military action.

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red line British  

noun

1. a point beyond which a person or group is not prepared to negotiate

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Etymology

Origin of red line

First recorded in 1960–65

Example Sentences

See Examples For:

red line

And with nominal yields, real yields, global rates and term premiums all moving in the same direction, a 5.2% yield is now the bright red line investors should watch.

From MarketWatch ● Jul. 24, 2026

England head coach Tuchel said the ruling set a dangerous precedent, while Uefa said intervening to effectively cancel a suspension at a tournament "crossed a red line".

From BBC ● Jul. 7, 2026

Now Mexico’s leaders are drawing a red line.

From The Wall Street Journal ● Jun. 6, 2026

He could not stay within the one red line that the court drew for him.

From Slate ● Jun. 1, 2026

The red line moved upward quite steeply, that was true.

From "Rowan of Rin" by Emily Rodda