BCE stands for "Before the Common Era." It is a notation used in the Gregorian calendar to refer to years before the start of the current era, which is commonly referred to as AD or "Anno Domini."
The use of BCE is often preferred by historians and scholars who wish to avoid religious connotations associated with the traditional BC (Before Christ) and AD (Anno Domini) notations. BCE is essentially equivalent to BC, but it is a more neutral and inclusive term.
The Gregorian calendar is the most widely used civil calendar in the world today. It is based on the birth of Jesus Christ as the dividing point between BCE and CE (Common Era). BCE counts the years before this point, while CE counts the years after it.
By mastering the concept of BCE and its place within the Gregorian calendar, you will have a solid foundation for understanding historical timelines and dating systems.