The year 2021 AD has just begun. But what does the “AD” mean? Some people might remember that it means something like “Animal Dominoes.” It is actually a Latin term, “anno Domini,” which means “in the year of the Lord.”

The practice goes back to ancient times when dates were calculated according to the reign of the current monarch. This practice is common throughout the Bible but also in many records and writings by people of many cultures. This can be illustrated by some biblical examples:

• “In the fifth year of King Rehoboam…” (1 Kings 14:25)

• “In the year that King Uzziah died…” (Isaiah 6:1)

• “In the third year of the reign of Jehoiakim king of Judah…” (Daniel 1:1)

• “In the fifteenth year of the reign of Tiberius Caesar…” (Luke 3:1)

Of course, this meant that the calendar would be different in each kingdom, and the calendar would change every time a new king was crowned. If a new king was crowned in the middle of a year, would that date become the start of a new year, meaning that some “years” would be shorter than others? Or would some years be shared by two kings, and if so, would that be counted as two years instead of one? The lack of clarity makes it very difficult to date events precisely in the ancient world. 

2021 AD means, “in the 2021st year of the reign of the Lord,” that is, “in the 2021st year since Jesus’ birth” (or possibly His incarnation). This method of dating was first suggested in 525 AD and gradually became the standard practice in Europe in the Middle Ages. It has proved so useful that it has continued into the present.

Of course, in more recent years, those who are not Christians have begun to use an alternate term: 2021 CE, meaning “the 2021st year of the Christian Era,” later further secularized to mean “the 2021st year of the Common Era.”

Those of us who are Christian should still be saying “2021 AD,” meaning “in the 2021st year of our Lord.” By doing so, we are declaring our allegiance to the Lord Jesus Christ and affirming that His kingdom supersedes all other kingdoms.