overcoil

[ oh-ver-koil ]

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.

Word History and Origins

Origin of overcoil¹

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

Example Sentences

Used in chronometers and other fine time pieces where the spring is an overcoil.

From Project Gutenberg