A chronometer is a specific type of watch that has been tested and certified to meet certain precision and environmental standards. The term was coined in 1714 by clockmaker Jeremy Thacker of Beverly England in regards to his invention of a clock concealed in a vacuum chamber.
The term chronometer was also used for a Marine Chronometer, a device that enabled accurate marine navigation along the high seas through the 20th Century and is still used as a back-up for global satellite navigational systems which replaced it.
Today a chronometer is a Swiss-made timepiece awarded the certification of precision by the COSC (Official Swiss Chronometer Test Institute), which has undergone a rigorous series of testing conducted by the Institute.
Swiss-made automatic, mechanical and quartz watches are awarded chronometer certification by the COSC for both 3-hand and chronograph models.
Many of today’s most-prestigious watchmakers, including TAG Heuer, Rolex, Omega, Invicta, Chopard, Graham, Baume & Mercier, Zenith, Ulysse Nardin, Tissot and Breitling feature COSC certified chronometers in their timepiece assortments. In fact, all Breitling watches, automatic, mechanical and quartz watches for both men and women are certified chronometers.
Outside of Switzerland, the Japan Chronometer Inspection offers similar certification for Japanese made timepieces and the Seiko brand has received numerous chronometer certifications by the Japanese Institute.