Have you ever wondered what AM and PM mean? These two abbreviations are used to indicate the time of the day, but not everyone knows what they stand for. In this article, we will explore the meaning of AM and PM, their origin, and how they are used today.
What Does AM Mean?
The abbreviation AM stands for ante meridiem, which is a Latin term that means "before noon." Therefore, AM refers to the time between midnight and noon. For example, 8:00 AM is eight hours after midnight and eight hours before noon.
The use of AM dates back to ancient Rome when people used sundials to tell time. The Romans divided the day into 12 hours of daylight and 12 hours of darkness, starting at sunrise and ending at sunset. Therefore, the first hour after sunrise was called "prime" and the last hour before sunset was called "twelve."
However, as the length of daylight varies throughout the year, the length of the hour also varies. Therefore, in the 14th century, mechanical clocks were invented, which allowed for more precise timekeeping. The clockmakers divided the day into 24 hours of equal length, starting at midnight and ending at midnight. Hence, the term AM was born.
What Does PM Mean?
The abbreviation PM stands for post meridiem, which is a Latin term that means "after noon." Therefore, PM refers to the time between noon and midnight. For example, 8:00 PM is eight hours after noon and eight hours before midnight.
Similar to AM, the use of PM dates back to ancient Rome. However, the Romans did not have a specific term for the afternoon hours. Instead, they used phrases like "the ninth hour after sunrise" or "the eleventh hour before sunset." It was only after the invention of mechanical clocks that the term PM was created.
How are AM and PM Used Today?
Today, AM and PM are widely used to indicate the time of the day. Most digital clocks, watches, and smartphones display time in the 12-hour format, with AM and PM indicators. However, some countries, such as the United States and Canada, also use the 24-hour format, which does not require AM and PM.
It is essential to understand the difference between AM and PM, especially when scheduling appointments, meetings, or flights. For example, if someone asks you to meet them at 8:00, you need to clarify whether it is 8:00 AM or 8:00 PM.
Conclusion
AM and PM are two abbreviations used to indicate the time of the day. AM stands for ante meridiem, which means "before noon," and PM stands for post meridiem, which means "after noon." These terms were created during the invention of mechanical clocks in the 14th century and are still widely used today.