white line

American  

noun

1. a stripe of white paint, tiles, or the like, that marks the center or outer edge of a road.

2. a white layer in a horse's hoof.

3. any blank or white part, line, stripe, or margin.

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white line British  

noun

1. a line or strip of white in the centre of a road to separate traffic going in different directions

2. a white lamination in the hoof of a horse

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Etymology

Origin of white line

First recorded in 1590–1600