What is AM? What is PM? Differences between AM and PM in English

AM and PM are terms used to indicate time. However, many people still use these terms incorrectly. Let's quickly learn how to write, read, and use AM and PM as well as discover the AM and PM meaning in the article below!

I. What is AM?

In English, AM is pronounced /ˌeɪˈem/ and is used to refer to the time between twelve o'clock at night and twelve o'clock in the middle of the day. Example:

• The first election results are expected around 9 AM.

• We fly out of Singapore late in the evening and arrive in New York at 7 AM the next morning. 

II. What is PM?

PM means day or night? In English, PM is pronounced /ˌpiːˈem/ and is used to refer to the time between twelve o’clock in the middle of the day and twelve o’clock at night; in the afternoon or evening or at night. Example:

• We'll be arriving at about 4 PM. 

• The 6 PM train is usually very crowded. 

III. Historical origin of AM and PM

The terms ante meridiem (am) and post meridiem (pm) come from Latin, meaning before noon and after noon, respectively. People typically divide a 24-hour day into 12 hours for each half of the day and use the AM and PM designations to distinguish between morning and afternoon/evening.

IV. Comparing AM/PM to 12-hour and 24-hour systems

Most countries in the world currently use the 24-hour system. However, the 12-hour format (AM and PM) is officially used in some countries, including the United States, Canada (except Québec), Australia, New Zealand, and the Philippines. So do we use 12 AM or PM?

Notes:

• "AM" is an abbreviation for "Ante Meridiem" (before noon).

• "PM" is an abbreviation for "Post Meridiem" (after noon).

• "Noon" is often used instead of 12 PM.

• "Midnight" is often used instead of 12 AM.

V. Notes on writing AM, PM, a.m, p.m

AM, PM, a.m, p.m are all correct ways to express time. However, you need to pay attention to the "periods" and "spacing" between the numbers and letters. Example:

• I have a class at 2 PM today. (✅)

• John studies at 8 AM in the morning. (✅)

• The meeting ended at 11 a.m. (✅)

• You need to be there by 9:00a.m. (❌)

Let’s read the dialogues using AM and PM below!

VII. Exercises on using AM and PM

To better understand the use of AM&PM in English, let's complete the practice exercise below!

1. Exercise: Find and correct the errors in the sentences below

1. My alarm goes off at 6 PM every morning.

2. The meeting is scheduled for 10a.m tomorrow.

3. We have a lunch reservation at 12a.m.

4. Her flight arrived at 3 AM yesterday afternoon.

5. The gym opens at 5 a.m, so I can work out before work.

6. Our class starts at 8a.m sharp.

7. The concert will begin at 7 AM tomorrow evening.

8. I usually go to bed around 11a.m.

9. Breakfast is served from 7a.m to 9a.m at the hotel.

10. The movie screening is at 4 a.m today.

2. Answer

Overall, PREP hopes this has provided you with a comprehensive understanding of the concept and usage of AM and PM in English. Keep following PREP to continue updating your valuable English knowledge!