Hairpin
A pin or stick used to hold hair in place, from small sprung grips to ornamental sticks.
Also: bobby pin, kirby grip, hair stick
Hairpins hold hair in place. A bobby pin, or kirby grip in Britain, is a small sprung pin with a ridged side; a U-shaped hairpin holds buns and chignons without gripping tightly. Ornamental hairpins and hair sticks have a long history: the Korean binyeo and Chinese hairpins fixed married women's buns, and the Japanese kanzashi decorate the hairstyles of geisha and brides. A good updo hides most of its pins.