Skeletonised

Skeletonising means removing metal from the plates, bridges and sometimes the dial of a watch so that the mechanism behind them can be seen. The British Museum uses "skeletonised watch" as a catalogue object type. Its record for a watch signed "H. DELOLME LONDON" but recorded by the museum as Swiss-made, about 1900 (museum number 1958,1201.974), describes a "three-quarter plate skeletonised movement, incorporating Royal Arms" with a club-tooth lever escapement, and the curatorial notes the "back plate pierced out including the Royal coat of arms", carrying the motto "DIEV ET MON DROIT", with an engraved balance cock.

The work is not necessarily hand work, nor confined to the back. The museum's record for a watch by the New England Watch Company, 1912 (museum number 1958,1201.1381), reads "Watch. Duplex escapement; skeletonised plates and dial. Metal-gilt dial. Nickel plated case; glazed both sides", and the curatorial comments call it "a less common type as it has a skeletonized movement and dial, which allows the mechanism to be seen from both sides through glasses at the front and back". The same notes record that its parts were industrially made, "some of them simply pressed from brass sheet".

No authority defines the term. The British Museum applies the word to objects without defining it, and no threshold says how much metal must be removed before a movement counts as skeletonised. ISO/TC 114, the ISO committee for horology, holds eight standards directly — on jewels, control-position symbols, wrist-chronometers, battery life, chemical regulatory compliance, hard-material external parts and watch batteries — and none addresses decoration. The word is recorded here as museum cataloguing practice and trade usage, not as a specification.