Chronology (from Greekχρονολογία - chronologia, from χρόνος - chronos, "time" + λόγος - logos, amongst others "the study of") is a chronicle or arrangement of events in their occurrence order. General chronology is the science of locating and resolution of temporal sequence of past events in time.
Chronology is part of periodization. It is also part of the discipline of history including earth history and geochronology dependent disciplines (See Prehistoric chronologies below) and the earth sciences. When used for specific examples, a chronology is a sequential arrangement of events, such as a chronicle or, particularly when involving graphical or literary elements, a timeline.
Anno Domini (Medieval Latin: In the year of (the/Our) Lord), abbreviated as AD or A.D., is a designation used to number years in the Julian and Gregorian calendars. More fully, years may be also specified as Anno Domini Nostri Iesu (Jesu) Christi ("In the Year of Our Lord Jesus Christ").
The calendar era which it numbers is based on the traditionally reckoned year of the conception or birth of Jesus. Before Christ, abbreviated as BC or B.C., is used in the English language to denote years before the start of this epoch.