Meaning of overcoil

o•ver•coil

Pronunciation: (ō'vur-koil"), [key]
— n. Horol.
  1. a fixed end of a spiral hairspring, consisting of an upwardly and inwardly bent continuation of the outermost coil of the spring: used to offset the asymmetry of the common spiral spring when tight, which impairs isochronism.
  2. a hairspring having such a fixed end.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.