guardrail

American  

[gahrd-rayl] / ˈgɑrdˌreɪl /

noun

• guardrails
  plural

1. Also guardrailing. a protective railing, as along a road or stairway.

2. Railroads. a rail laid parallel to a track to prevent derailment or to keep derailed rolling stock from leaving the roadbed.

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guardrail British  

/ ˈɡɑːdˌreɪl /

noun

1. a railing at the side of a staircase, road, etc, as a safety barrier

2. Also called (Brit): checkrail. railways a short metal rail fitted to the inside of the main rail to provide additional support in keeping a train's wheels on the track

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Other Word Forms

Noun Inflected Forms

• guardrails
  plural

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Etymology

Origin of guardrail

First recorded in 1825–35; guard + rail ¹

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Explanation

A guardrail is a strong fence at the side of the road that can help protect drivers from serious injury. On a highway, center guardrails make it easier to avoid colliding with a car going the opposite direction. Guardrails protect cars from hitting large roadside objects like trees and signs, or from hazards such as steep hills beside the highway. Additionally, guardrails are designed to keep cars upright, even when they strike the rail at fairly high speeds. In some places, low, protective fences around public spaces are also called guardrails — in this case, they're guarding against pedestrian injuries. "Stay back from the guardrail around the lion enclosure!"

Example Sentences

See Examples For:

guardrail guardrails

The plan is simply this: If you hit the guardrail on the high end or the low end, you will increase or decrease spending until you get back to that 85% chance of success.

From MarketWatch ● Oct. 2, 2026

The man, the driver and sole occupant of the car, was traveling north on Grand Avenue and veered off the roadway and through a guardrail.

From Los Angeles Times ● Sep. 11, 2026

The tools switch on for the new year the same season the guardrail comes off.

From Slate ● Aug. 21, 2026

“Even if you can find a use case or some utility for it, you cannot actually guardrail away some of these inherent harms,” she said.

From Salon ● Aug. 17, 2026

We sprinted the other way, across the street, hopped an old rusty guardrail and ran along this grassy part near the beach.

From "We Were Here" by Matt De La Peña

“Raising the idea of guardrails and accountability, if it improves the program, I’m all for it,” said Sam Wilson, a senior vehicle analyst with the Union of Concerned Scientists.

From Los Angeles Times ● Oct. 18, 2026

Insurance—or the inability to acquire it at an affordable price—has the potential to help police AI by imposing guardrails on both developers and users as a condition of coverage, brokers and insurers say.

From The Wall Street Journal ● Oct. 16, 2026

So those are the guardrails to consider — spend between $10,000 and $15,000 a month.

From MarketWatch ● Oct. 15, 2026

Concerns about AI guardrails have soared after models developed by OpenAI and Anthropic were involved in security incidents during testing, piling on pressure to regulate the technology.

From Barron's ● Oct. 14, 2026

If Annabelle ran on US Route 12 and not the desolate 200, she’d be facing blind curves, and navigating tight spaces next to guardrails and steep, forested cliffs.

From "A Heart in a Body in the World" by Deb Caletti

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