Glossary

Listed below are a number of frequently used technical terms and a brief description of their meaning.

• Chronometer/ Chronometre. This refers to a watch movement that has been subject to exhaustive testing and has achieved the required level of performance. Rolex use the term Superlative Chronometer Officially Certified on their models


• Chronograph. This refers to a watch that is designed to measure lapsed time, also known as a Stopwatch. Also referred to as a Cosmograph by Rolex.


• Oyster. This is a term used by Rolex to describe their
  Water Resistant model range. It specifically relates to the method of case construction and winding crown design.


• Perpetual. This is again used by Rolex to describe their Automatic mechanical watches.


• Crown. Also known as the Winder or Button. This is used to wind the watch and reset the time, day, date etc. On many Water Resistant models this will screw into the watch case to improve protection.


• Bezel. This relates to the ring surrounding the crystal glass. This can often be set with Diamonds or have specific functions on sports models. Measure lapsed time, calculate average speed etc.


• Sapphire Crystal. This relates to a watch crystal made from synthetic Sapphire. These are highly scratch resistant. On many models they also have an anti-reflective coating (Breitling, Omega).


• Jewel A precious stone (usually synthetic Ruby) that is used as a bearing to reduce friction and wear, and therefore prolong the life of a watch movement.


• Rolesium. A term used by Rolex to describe a case metal mixture of Steel and Platinum.


• Rolesor. A term used by Rolex to describe a case and /or Bracelet mixture of Gold and Steel.


• Serial Number. An individual reference number relating to an individual watch, this can often be used to date the watch.


• Bi Metal. A term used to describe a watch made from 2 different metals, (see also Rolesor).

• E.O.L. (End of Life) Indicator. This is a function built into many high quality Quartz Watches to indicate when the Battery is nearing the end of its life. The second hand will start to move in 2 or 3 second steps. This is often used by Omega, TAG Heuer and Breitling.

• Battery Life. This refers to the length of time that a Quartz Watch will continue to operate with a new battery fitted. This is typically 12 to 18 months but can vary greatly depending on the type of battery fitted ( Silver Oxide or Lithium) and any additional functions that the watch has ( Alarm, Stopwatch etc).

• Power Reserve. This refers to the length of time that a mechanical watch will continue to operate once fully wound. This is typically 36 to 42 hours but can vary from model to model (refer to specific instructions for each watch).

• Time Keeping Accuracy. Quartz and Mechanical watches have greatly differing levels of accuracy, this is due to the different methods by which they measure time. It is very important that you are aware of the differences before you purchase your watch.  Watches can generally be divided into the following 3 different categories.​

1. Chronometer. To achieve Chronometer status the watch must be accurate to within the scale of -4 / +6 seconds per day.
2. Non Chronometer rated Mechanical Watch. A typical watch of this type will normally operate within the range of -4 / +10 seconds per day.
3. Quartz (battery) Watch. These are inherently accurate and will usually operate to within 1/2 second per day.

• Water Resistance. This is usually shown as Depth measured in Meters. Many watches will have the degree of Water resistance printed on the Watch dial or case back. Rolex only state the depth on a limited number of models. All Rolex Oyster Models without a stated depth rating are Water Resistant to 100 Meters. Remember that Water Resistance is not a permanent feature and relies on the Watch being worn as per the instructions as well as regular maintenance.

• Servicing. All Watches require regular servicing to ensure that they continue to operate efficiently and to prolong their useful life. Most manufacturers recommend that their watches are serviced every 4 to 5 years. This will involve a full strip down and inspection of all internal parts, which are then cleaned and completely reassembled using the finest lubricants. The case and bracelet are also cleaned and re polished before the watch is regulated and thoroughly tested.

• New Retail Price
  This is the price you would pay if you were to buy the watch new.  Where a watch is no longer in production this is the estimated price to find an equivalent model.