Watch glossary: L, M
A chronograph function that lets the wearer time segments of a race. At the end of a lap, he stops the timer, which then returns to zero to begin timing the next lap.
Leap or bissextile years have 366 days and occur every 4 years (with some exceptions, Calendar, Gregorian). Some watches display this datum.
A caliber typical for pocket-watches, characterized by the seconds hand fitted in the axis of the winding-stem.
Ancient French measuring unit maintained in horology to indicate the diameter of a movement. A line equals 2.255mm. Lines are not divided into decimals; therefore, to indicate measures inferior to the unit, fractions are used.
LIQUID CRYSTAL DISPLAY or LCD
A digital watch display that shows the time electronically by means of a liquid held in a thin layer between two transparent plates. All LCD watches have quartz movements.
To reduce friction caused by the running of wheels and other parts. There are points to be lubricated with specific low-density oils such as the pivots turning inside jewels, the sliding areas between levers, and the spring inside the barrel (requiring a special grease), as well as numerous other parts of a movement.
Double extension of the case middle by which a strap or bracelet is attached. Normally, straps and bracelets are attached with removable spring bars.
LUMINESCENT or LUMINOUS
Said of materials applied on markers and/or hands, emitting the luminous energy previously absorbed as electromagnetic light rays. Tritium is no longer used and was replaced by other substances having the same emitting powers, but with virtually zero radioactivity, such as Super-LumiNova and Lumibrite.
This and the barrel make up the driving element of a movement. It stores and transmits the power force needed for its functioning.
A mechanical movement in which winding is performed by hand. The motion transmitted from the user's fingers to the crown is forwarded to the movement through the winding stem, from this to the barrel through a series of gears and finally to the mainspring.
A large-sized chronometer watch enclosed in a box (therefore also called box chronometer) mounted on gimbals and used, on board of ships, to determine the respective longitude.
Elements printed or applied on the dial, sometimes they are luminescent, used as reference points for the hands to indicate hours and fifteen- or five-minute intervals.
The mean time of the meridian of the Greenwich Observatory, considered the universal meridian, is used as a standard of the civil time system, counted from midnight to midnight.
A feature, usually consisting of a graduated scale on the watch's bezel, that lets the wearer translate one type of measurement into another - miles into kilometers, for instance, or pounds into kilograms.
A movement powered by a mainspring, working in conjunction with a balance wheel. Most watches today have electronically controlled quartz movements and are powered by a battery. However, mechanical watches are currently enjoying a resurgence in popularity.
Element positioned on the regulator, allowing to shift it by minimal and perfectly gauged ranges so as to obtain accurate regulations of the movement.
MICRO-ROTOR, see rotor.
MILITARY TIME or 24-HOUR TIME
When time is measured in 24-hour segments. To convert 12-hour time into 24-hour time, simply add 12 to any p.m. time. To convert 24-hour time into 12-hour time, subtract 12 from any time from 13 to 24.
MINERAL CRYSTAL or MINERAL GLASS
Watch crystal that has been tempered (heat treated) to increase its hardness and scratch resistance.
MINUTE REPEATER, see repeater.
Self-contained mechanism, independent of the basic caliber, added to the movement to make an additional function available: chronograph, power reserve, GMT, perpetual or full calendar (s).
A function available in many watches, usually combined with calendar-related features. The moonphase disc advances one tooth every 24 hours. Normally, this wheel has 59 teeth and assures an almost perfect synchronization with the lunation period, i.e. 29.53 days (in fact, the disc shows the moonphases twice during a single revolution). However, the difference of 0.03 days, i.e. 44 minutes each month, implies the need for a manual adjustment every two and a half years to recover one day lost with respect to the real state of moonphase. In some rare case, the transmission ratio between the gears controlling the moonphase are calculated with extreme accuracy so as to require manual correction only once in 100 years.
MOTHER OF PEARL
Iridescent, milky interior shell of the fresh water mollusk that is sliced thin and used on watch dials. While most have a milky white luster, mother-of-pearl also comes in other colors such as silvery gray, gray blue, pink, and salmon.
The entire mechanism of a watch. Movements are divided into two great families: quartz and mechanical; the latter are available with manual or automatic winding devices.
on Jan 11, 2010 | Watches