The surfaces or edges of watch components can be honed and polished with the help of a lapping machine (or polishing machine). This polishing enhances the visual appearance and value of a movement.

Abbreviation for "liquid crystal display." When pressured by an electric field, a liquid crystal film refracts incident light. This feature makes these crystals very useful for digital quartz watches. LCDs replaced LEDs in the mid-1970s. Rather than generating its own light, an LCD refracts light falling on it. The advantages of this are: - less electric current is used - the display is continuously visible and does not need to be specially activated first - good visibility is provided in different lighting conditions - the assembly requires no moving parts. In its simplest version, an LCD consists of two glass plates, each of which is coated on its inner surface with a layer of electrodes. Between the two plates are nematic (filiform) liquid crystals that have elongated molecules and a nearly parallel sorting structure. The liquid crystals undergo excitation when the electrodes are exposed to an electric field. If no field is present, the coating is clear and transparent. When current flows through it, the coating becomes turbulent, refracts light and appears cloudy.

According to the Julian calendar, every four years has an extra day added at midnight on 28 February. Because of this additional day (29 February), a leap year has 366 days, instead of the 365 days that make up a normal year.

Abbreviation for "light-emitting diode." These optoelectric elements were used in the 1970s to tell the time on quartz watches. Because the display absorbs so much energy when it is on, it was kept dark unless it was specially activated by pressing a button. This defect soon led to its obsolescence, and the LED was replaced by the LCD display.

In this form of construction for watch movements, named after the French watchmaker Jean-Antoine Lépine, the wheels and balance wheel share a common plane and slide on one side of the plate under the bridges and cocks. Moreover, in a Lépine calibre, the winding crown with adjustment, the centre of the dial and the axis of the seconds hand are all aligned along the same line.

This is currently the most commonand used type of escapement in mechanical watches. It was invented around 1710 by English watchmaker George Graham (the so-called "Graham deadbeat escapement") for use in large clocks. Beginning in 1757, Graham's student Thomas Mudge gradually developed the anchor escapement so that it could also be used in pocket watches. Portable watches are based on various types of anchor escapements. Their names vary according to the shape of the pallets and include: the English lever escapement (which has pointed teeth on the escape wheel), the Glashütte lever escapement, the Swiss lever escapement, and the pallet escapement. The Swiss anchor escapement unquestionably dominates the field nowadays. The pin-pallet escapement is quite rare and is typically found only in very simple cases.

Traditional unit used to measure the size of clock movements. Ligne is derived from the ancient French foot or "pied due roi." A common diameter for circular movements is 11 lignes. Rectangular movements sometimes measure 8¾ x 12 lines. One line is equivalent to 2.2558 millimeters. One French foot is equivalent to 12 inches or 144 lines. A foot is abbreviated with a single apostrophe ('); an inch is abbreviated with twin apostrophes (''); a line is abbreviated with three apostrophes (''').

During a lunation, which is equivalent to about 29.5 days, the moon progresses through a complete cycle of its phases: that is, from the new moon, first quarter, to the full moon and last quarter, to the next new moon.