High Quality Content by WIKIPEDIA articles! A hairpin turn (also hairpin bend, hairpin corner, etc.), named for its resemblance to a hairpin/bobby pin, is a bend in a road with a very acute inner angle, making it necessary for an oncoming vehicle to turn almost 180° to continue on the road. Such turns in ramps and trails may be called switchbacks in American English, by analogy with switchback railways. In British English `switchback` is more likely to refer to a heavily undulating road—a use extended from the rollercoaster and the other type of switchback railway.