Homonym: AD (Advertisement)
"AD" stands for "Anno Domini," a Latin term meaning "in the year of our Lord." It is used to label years in the Gregorian calendar, which is the calendar system most widely used today. The years are counted from the traditional birth year of Jesus Christ, with years before this event labeled as "BC," or "Before Christ."
The concept of AD was introduced by the monk Dionysius Exiguus in the 6th century. It helps to organize historical events chronologically, allowing for a clearer understanding of timelines in history, religion, and culture. The use of AD has become standard in many parts of the world, facilitating communication across different cultures and languages.