Search Result for "hairspring": 
Wordnet 3.0

NOUN (1)

1. a fine spiral spring that regulates the movement of the balance wheel in a timepiece; 



The Collaborative International Dictionary of English v.0.48:

Hairspring \Hair"spring`\ (-spr[i^]ng`), n. (Horology)
   The slender recoil spring which regulates the motion of the
   balance in a timepiece.
   [1913 Webster]


WordNet (r) 3.0 (2006):

hairspring
    n 1: a fine spiral spring that regulates the movement of the
         balance wheel in a timepiece