Accutron

The first electronic watch, controlled by a tuning fork and launched by Bulova in 1960.

Bar

Unit of measure to indicate a watch's water-resistance, specifically its capacity to resist pressure, based on standard atmospheric pressure defined as 101.325 kilopascals (kPa) equivalent to...

Calibre

Synonym of size. Sully used this term circa 1715 to denote the layout and dimensions of the different movement pillars, wheels, barrel, etc. Since then "calibre" has been used to...

Day

Period between the rising and setting of the Sun. A 24-hour interval, determined by the Earth's rotation on its axis.

Engine turn

To cut metal with decorative engraving by hand or using an engine turning machine.

Flirt (independent seconds)

A small rod, driven by a separate train, whose end meshes with the escape-pinion's leaves. The flirt is released every second and makes one complete revolution. This movement is transferred to the...

Glucidur (Glucydur)

A highly elastic, hard, amagnetic and corrosion-proof alloy used to make monometallic balances, escapements and balance-springs.

Horn

That part of a watch case to which the strap is attached. Horns come in various shapes and are attached to the case middle.

Isochronal (Isochronous)

Recurring at regular intervals. The oscillations of a pendulum or balance are isochronal when their duration is the same regardless of their amplitude.

Jade

Jade is a gem group with jadeite and nephrite as the two varieties. Jadeite is the variety that ranges in colour from green to white to lilac to brown to almost black. Nephrite, the more ancient...

Knot

A raised mineral inclusion in a diamond found at the surface.

Light-Emitting Diode (LED)

A segmented luminous source used to display numerals on electronic digital watches. Operated by a push-button.

Master

A watchmaker who has presented his masterpiece or test piece.

Onyx

A black agate that is often found as watch dials.

Pivot

A part that runs in a fixed support (bearing).

Quartz

Silicon dioxide. Also called rock crystal. Quartz has the specific property of vibrating at a very high frequency (32 MHz) placed under electric current. Under certain conditions, it...

Rack

A straight or curved bar with teeth.

Shockproof

Designed to withstand shocks without being damaged. See also shock absorber and Incabloc®.

Tsavorite

A rare, deep green variety of grossular garnet. The green colour comes from vanadium and chromium. A Tsavorite of over two carats are very rare. This gemstone has a hardness of 7.5 and a specific...

Under-dial work

Collective term for the mechanisms, such as for striking, a calendar or motionwork, between the dial and the dial plate.

Vermeil

Silver covered with a thin layer of gold.

Wind

The action of tightening the mainspring coiled inside the barrel by means of the winding crown (in a hand-wound watch) or the rotor (in a self-winding watch).

Year

A four-digit indication of the current year that changes automatically at midnight on December 31st.

Zodiac

At the heart of countless legends and beliefs, since ancient times precious stones have had symbolic value. From the Jews to the Egyptians, each culture and religion has given a different meaning...