AM and PM: What Do They Mean?
How does the 12-hour clock system work? Is midnight 12 am or 12 pm?
Elsewhere on timeanddate.com
What Is Daylight Savings Time (DST)?
About 40% of countries use Daylight Saving Time. Learn how it works, what makes it controversial, and why it’s not actually saving any daylight.
12 Months of the Year
Why are there 12 months? How long are they, and what do the month names mean?
UTC: Coordinated Universal Time
What is UTC time? Find out how Coordinated Universal Time is measured, what it means for you, and how you can use it to state the time in any time zone.