overcoil

American  

[oh-ver-koil] / ˈoʊ vərˌkɔɪl /

noun

Horology.

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.

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Etymology

Origin of overcoil

First recorded in 1880–85; over- + coil ¹

Example Sentences

Breguet has come up with a technique to bend silicon in a way that echoes the form of its original “Breguet overcoil” spring, conceived in 1795.

From New York Times