Chronometry (from Greek χρόνος chronos, "time" and μέτρον metron, "measure") is the science of the measurement of time, or timekeeping. Chronometry provides a standard of measurement for time, and therefore serves as a significant reference for many and various fields of science. The importance of the accuracy and reliability of measuring time provides a standardized unit for chronometric experiments for the modern world, and more specifically scientific research. Despite the coincidental identicality of worldwide units of time, time produces a measurement of change and is a variable in many experiments. Therefore, time is an essential part of many areas of science. It should not to be confused with chronology, the science of locating events in time, which often relies upon it. Also, of similarity to chronometry is horology, the study of time, however it is commonly used specifically with reference to the mechanical instruments created to keep time, with examples such as stopwatches, clocks, and hourglasses. Chronometry is utilised in many areas, and its fields are often derived from aspects of other areas in science, for example geochronometry, combining geology and chronometry. Early records of time keeping are thought to have originated in the Paleolithic era, with etchings to mark the passing of moons in order to measure the year. And then progressed to written versions of calendars, before mechanisms and devices made to track time were invented. Today, the highest level of precision in timekeeping comes with atomic clocks, which are used for the international standard of the second. Etymology Chronometry is derived from two root words, chronos and metron (χρόνος and μέτρον in Ancient Greek respectively), with rough meanings of "time" and "measure". The combination of the two is taken to mean time measuring. In the Ancient Greek lexicon, meanings and translations differ depending on the source. Chronos, used in relation to time when in definite periods, and linked to dates in time, chronological accuracy, and sometimes in rare cases, refers to a delay. The length of the time it refers ranges from seconds to seasons of the year to lifetimes, it can also concern periods of time wherein some specific event takes place, or persists, or is delayed. The root word is correlated with the god Chronos in Ancient Greek mythology, who embodied the image of time, originated from out of the primordial chaos. Known as the one who spins the Zodiac Wheel, further evidence of his