hair·pin
noun/ˈheəpɪn/
/ˈherpɪn/
- a small thin piece of wire that is folded in the middle, used by women for holding their hair in place
发夹 - (also hairpin turn, British English also hairpin bend, North American English also hairpin curve)a sharp U-shaped bend in a road, especially a mountain road
（尤指山路的）急转弯