hairspring

n fine spring in a watch, controlling the balance-wheel （表的）游丝（控制摆轮的细小弹簧）.

hair-line, hair-net, hair-oil, hair-piece, hair-raising, hair-restorer, hair-slide (also slide), hair-splitting, hair-style, hair-stylist, hair-trigger, hairbrush, haircloth, haircut, hairdress, hairdresser, hairdressing, hairiness, hairless, hairpin, hairy, hake, halal, halal (also hallal), halcyon, hale, half, half board, half cock, half holiday, half moon, half nelson, half pay, half-and-half, half-back, half-baked, half-brother, half-caste (also half-breed), half-crazed, half-crown,