noun
- a slender U-shaped piece of wire, shell, etc., used by women to fasten up the hair or hold a headdress.
adjective
- (of a road, curve in a road, etc.) sharply curved back, as in a U shape: a hairpin turn.
noun
- a thin double-pronged pin used by women to fasten the hair
- (modifier) (esp of a bend in a road) curving very sharply
also hair-pin, 1788 (two words), from hair + pin (n.). A hairpin turn, etc., is from 1906. Hairpin (or clothespin) was American English slang for “person” c.1880-1910, especially in the expression “That’s the kind of hairpin I am.”