Definition

1. Noun:
   • A highly accurate timekeeping instrument: A chronometer is a precise clock designed to maintain accurate timekeeping over long periods, especially under varying conditions of temperature, pressure, or motion.
   • A navigational instrument: Historically and specifically, a chronometer is an exceptionally accurate clock used for determining longitude at sea by comparing local time to a known reference time (e.g., Greenwich Mean Time).

Examples of Usage

• Noun:
  • The ship's captain relied on the marine chronometer to calculate the vessel's longitude during the long voyage.
  • This antique chronometer, built in the 18th century, is still remarkably accurate.

Advanced Usage

• "Certified chronometer": A timepiece (often a wristwatch) that has passed a series of precision tests in an official observatory or institute (e.g., COSC - Contrôle Officiel Suisse des Chronomètres).
  • His wristwatch is a certified chronometer, guaranteeing its accuracy within strict tolerances.

Variants and Related Words

• Chronometric (adj): Relating to the measurement of time or chronometers.
  • The chronometric data was essential for the experiment.
• Chronometry (n): The science of accurate time measurement.
  • His research is in the field of chronometry.

Synonyms

• Timekeeper: A general term for any device that measures time.
• Precision clock: Emphasizes the accuracy of the instrument.

Notes on Meaning

• While a chronometer is a type of clock, the term implies a standard of tested and certified accuracy, particularly for scientific or navigational purposes. It is more specific than a general clock or watch.
• In modern contexts, "chronometer" often refers to high-precision wristwatches that have received official certification, not just any stopwatch or timer (which are more accurately called "chronographs").

Noun

1. an accurate clock (especially used in navigation)