Template:Time topics

Key concepts

Chronometry	UTC Universal Time TAI Unit of time Orders of magnitude (time)
Measurement systems	Italian six-hour clock Thai six-hour clock 12-hour clock 24-hour clock Relative hour Daylight saving time Chinese Decimal Hexadecimal Hindu Metric Roman Sidereal Solar Time zone
Calendars	Main types Solar Lunar Lunisolar Gregorian Julian Hebrew Islamic Solar Hijri Chinese Hindu Panchang Maya List
Clocks	Main types astronomical astrarium atomic quantum hourglass marine sundial watch 24-hour wristwatch mechanical stopwatch water-based Cuckoo clock Digital clock Grandfather clock History Timeline

Time in science

Geology	Geological time age chron eon epoch era period Geochronology Geological history of Earth
Physics	Absolute space and time Arrow of time Chronon Coordinate time Instant Proper time Spacetime Theory of relativity Time ___domain Time translation symmetry Time reversal symmetry
Other fields	Chronological dating Chronobiology Circadian rhythms Clock reaction Glottochronology Time geography