📝 Abbreviation Rules in English

Some abbreviations are standard in writing (Dr., not Doctor, in a name; St. Clair, the city, not Saint Clair). In some situations, you may have a choice whether to abbreviate or spell out a word. Choose what seems suited to your writing purpose and your audience, and be consistent within each piece of writing.

What are standard practices for using abbreviations?

How do I use abbreviations with months, time, eras, and symbols?

📅 Abbreviations for Months

Sometimes, we use short forms (abbreviations) for the names of months. This is common in notes, calendars, and tables.

Use the abbreviation when you write a date, especially if space is limited.
Example: The meeting is on Jan. 15, 2025.
Example: Her birthday is Sept. 3.
If you are writing a full sentence and have enough space, you can use the full month name.
Example: My favorite month is December.
Note: May, June, and July are not shortened.

⏰ Times

Use the abbreviations a.m. and p.m. only with exact times: 7:45 a.m.; 6:37 p.m.
The Modern Language Association (MLA) style calls for the use of lowercase letters.

📜 Historical Eras

When writing the abbreviations for eras, place AD before the year (AD 400) and all the others after the year (30 BC; 200 BCE; 855 CE).
AD: anno Domini (medieval Latin for “in the year of the Lord”)
CE: common era
BC: before Christ
BCE: before the common era

💲 How to Use Symbols and Words in Writing (MLA Style)

1. You can use symbols like $, %, or °. Sometimes you should write the word instead.
2. Use a symbol only with a number.
   Example: 10%, $5, 20°
3. If you write the number in words, also write the unit in words.
   Example: twenty centimeters (not twenty cm)
4. If the number is long (more than two words), use numbers and symbols.
   Example: 345 cm (not three hundred forty-five centimeters)
5. Some exceptions: You can use numbers and symbols together for these:
   Money: $18
   Weight: 7 lbs. (pounds)
   Computer size: 24 KB (kilobytes)
   Time: 6:34 a.m.
   Length: 5″ (inches)
   Temperature: 32° (degrees)
   Decimal numbers: 8.3
   Addresses: 123 Main St.
   Dates: April 22, 2025
   Pages: page 15
6. For money, you can mix symbols, numbers, and words.
   Example: $25 million

👨🎓 Titles

Use either a title of address before a name (Dr. Terry Mortenson) or an academic degree after a name (Terry Mortenson, PhD), not both.

However, because Jr., Sr., II, III, and so forth are part of a name, you can use both titles of address and academic degrees: Prof. James Carter III; Michael Lee Sr., DDS.

DDS: Doctor of Dental Surgery

🏷️ Names and Terms

If you use a word or phrase many times in your writing, do this:
The first time, write the full name. Then, put the short form (abbreviation) in parentheses right after it.
After that, just use the abbreviation.

📚 Major Scholarly Abbreviations