BC
"BC" stands for "Before Christ," a designation used to label years in the Gregorian calendar that occurred before the estimated birth year of Jesus Christ. The system counts years backward from the year 1 AD (Anno Domini), with 1 BC being the year immediately before 1 AD.
The use of BC helps historians and scholars organize historical events chronologically. For example, the construction of the Great Pyramid of Giza is dated to around 2580 BC, indicating it occurred over 2,500 years before the start of the AD era. This system is widely used in Western history and education.