ab urbe condita absolute dating amino acid anno domini anno mundi archaeology archaeomagnetic dating asparagine astronomical chronology astronomical year numbering astronomy before present calendar canon of kings carbon chinese era name chronicle chronology chronostratigraphy circa common era cosmic calendar deep time dendrochronology egyptian chronology ephemeris era floruit forensic science galactic year geochronology geologic time scale geological history of earth geology glottochronology glycine gregorian calendar hindu units of measurement history iso week date ice core incremental dating islamic calendar isoleucine isotope geochemistry japanese era name julian calendar korean era name law of superposition lichenometry limmu lunar calendar lunisolar calendar metonic cycle milankovitch cycles molecular clock new chronology oceanography old style and new style dates optical dating paleobiology paleoclimatology paleomagnetism paleontology periodization proleptic gregorian calendar proleptic julian calendar racemization radiocarbon dating radiometric dating regnal year relative dating revised julian calendar roman calendar samarium-neodymium dating seleucid era sexagenary cycle solar calendar sothic cycle spanish era stratigraphy synchronoptic view taphonomy taxonomy tephrochronology thermoluminescence dating time timeline uranium-lead dating year zero