For example, 5 am is early in the morning, and 5 pm is late in the afternoon; 1 am is one hour after midnight, while 11 pm is one hour before midnight.Ante meridiem is commonly denoted as AM, am, a.m., or A.When the spelled-out version first appears in the narrative of the sentence, put the abbreviation in parentheses after it: If your reference has a group author, the name of the group can sometimes be abbreviated—for example, American Psychological Association can be abbreviated to APA.
Imagine being asked to pick up a friend at the airport at am on April 13.
Would you go there at midnight between April 12 and April 13? One way to overcome this problem is to sacrifice accuracy for clarity.
The 12-hour system divides the 24 hours of a day into two periods lasting 12 hours each. The abbreviations am and pm derive from Latin: Using numbers from 1 to 12, followed by am or pm, the 12-hour clock system identifies all 24 hours of the day.
The second period, marked pm, covers the 12 hours from noon to midnight.
The Egyptians are thought to be responsible for dividing the day into 24 equal parts.
One account suggests that this custom evolved because the Egyptians commonly used the base 12, counting the 3 joints in their fingers, not including the thumb.
Your friend could ask you to be at the airport at am on April 13 or, if the following midnight is meant, at pm on April 13. Here, refers to midnight at the beginning of the day while is midnight at the end of the day.
A 24-hour clock, sometimes referred to as military time, states the time according to the number of hours that have passed since midnight.
As with other abbreviations, spell out the name of the group upon first mention in the text and then provide the abbreviation.
If the name of the group first appears in the narrative, put the abbreviation, a comma, and the year for the citation in parentheses after it.
See more about this in our post on cite what you see.