Plural of curb; concrete or stone edges along streets and sidewalks, or restraints and limitations.
From Old French 'courbe' (curved), originally describing the curved chain or strap on a horse's bridle, later applied to the curved edges of streets.
It's wild that the same word refers to both a physical thing (the concrete edge) and an abstract action (to curb something)—the metaphor is so successful we forget they're connected.
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