red line

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.

red line

noun

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

Word History and Origins

Origin of red line¹

First recorded in 1960–65

Example Sentences

President Obama had called the use of chemical weapons there a “red line.”

From The Daily Beast

When the president as commander in chief draws a red line, it is critical that he act if the line is crossed.

From The Daily Beast

It was still the ‘red line’ period, right when things were tense.

From The Daily Beast

In Syria he made chemical weapons a “red line,” and then folded in the face of public outcry and congressional opposition.

From The Daily Beast

Would the red line be enforced if evidence proved that Assad had used chemical weapons?

From The Daily Beast

A wavering red line licked its way to the canyon-edge on the east side, wiped out the grass, and died on the bald rim-rock.

From Project Gutenberg

They watched silently until the dot had crawled over the circle's red line, heading toward its center.

From Project Gutenberg

As soon as I reached the field I saw her horns and the red line of her back above the waving heads.

From Project Gutenberg

Balaclava was on his list, but he didn't even know it was there that his gallant regiment formed the thin red line.

From Project Gutenberg

Her rather nervous lips were thin and closed, so that they only appeared as a delicate red line.

From Project Gutenberg