In American and Canadian English, the noun meaning the edge of a sidewalk or roadway is spelled curb. In varieties of English from outside North America, the word is spelled kerb. But everyone uses curb for the verb meaning to check or restrain and for the verb’s corresponding noun (e.g., curbs on spending).





Examples

For the noun meaning edge of a roadway, North American writers use curb—for example:

Authorities said they were on the sidewalk when a car jumped the curb and struck them. [New York Times] Shoma Okamoto stands by one of those now-pointless curbs that border a paved road that meanders through the featureless landscape. [Vancouver Sun] By mid-January, millions of trees have been dragged to the curb, where they wait unceremoniously to be picked up with the trash. [Chicago Tribune]






Outside North America, it’s kerb:

By hugging the kerb and not pedalling furiously to keep up with traffic they placed themselves at greater risk … [Guardian] The bus is believed to have mounted a kerb before striking a wall and then overturning near Central Station. [Irish Times] Eyewitnesses said the Ford Fairmont hit the kerb before swerving across the street and into a fence. [New Zealand Herald]

And all use curb for the verb meaning to check or restrain and for its corresponding noun—for example: