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Capitalization, Italics, Numbers, and Abbreviations

Capitalization, Italics, Numbers, and Abbreviations

Author: Sophia Tutorial

Differentiate between correct and incorrect use of capitalization, italics, numbers, and abbreviations in sentences.

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what's covered
In this lesson, you will learn about some of the most commonly used mechanical aspects of writing. Specifically, this lesson will cover:
  1. Capitalization
  2. Italics
  3. Numbers
  4. Abbreviations

1. Capitalization

The most common use of capitalization is to start a sentence.


She definitely knows what she's doing.

Another very common use of capitalization is in occurrences of the word "I."


I have no idea what I'm doing.

In this sentence, notice how both instances of "I" are capitalized, not just the one that begins the sentence.

Proper nouns, or words that name specific people, places, or things, should always be capitalized.


Last month, David visited Cincinnati.

Titles proceeding names should also have capitalization.


This afternoon, Principal Armstrong called my dad.

Note that in the above sentence, "dad" is not capitalized because it is not used as a title. "Dad" would only capitalized if it were to replace the name of the narrator's father.


This afternoon, Principal Armstrong called Dad.

Capitalization is used with directions that are names, but not for directions in general.


I'm from the South, but I'm driving north.

Likewise, names of countries, languages, holidays, days of the week, and months should be capitalized. However, the names of the seasons are not capitalized.


Monday was the official end of summer.

Finally, capitalization should be used in all major words and titles, including the first and last word.


My favorite book is The Sound and the Fury.

In this sentence, the "and" and the second "the" in the title are not capitalized, but the first "the" is because it is the beginning of the title.

did you know
Some writers write words or phrases in all caps to emphasize them. This usage is only acceptable in some internet-based writing (e.g., social media posts). All caps should not be used in academic writing.

2. Italics

Italics sometimes serve the same purpose as underlining, but since the advent of computer-based writing, the use of italics has been preferred. Currently, underlining is rarely appropriate.

Italics are frequently used in titles, especially titles of books, movies, musical works, journals, newspapers, and websites. However, most shorter works, such as poem and song titles, are typically placed in quotations.


I'm sure that Jay-Z's Black Album will stand the test of time, as will Lil Nas X's hit song "Old Town Road."

Italics are also sometimes used to indicate a foreign word.


She gave me a funny look when I asked for my espresso con panna.

Did you notice that "espresso" isn't italicized, even though it's an Italian word like those used in the phrase con panna? That's because, as a result of frequent use, espresso has been incorporated into the English language. Still, some words fall into a gray area between "foreign" and "adopted into English." It's up to the writer to decide whether or not to italicize a particular word or phrase.

Italics are also used to indicate emphasis.


Let us not forget, my client met the victim only after the supposed crime was committed.

When using italics, especially for emphasis, it's important to avoid overuse. As with all punctuation, too-frequent use reduces meaning and increases distraction - and even annoyance - for readers.

3. Numbers

Though they're overlooked by some writers, there are rules for writing numbers:

  • Spell out numbers less than 10, and use numerals for numbers greater than or equal to 10.
  • Spell out numbers that begin a sentence, or rewrite the sentence so that the number appears later.
These rules work well in most, but not all, situations. Writers must observe the usage standards that apply to a particular writing project or genre.

The most important rule is to be consistent. Because, in most cases, the rules for writing out (or not writing out) numbers are not clearly stated, writers must often decide which standard to apply. Once a rule has been established, it must be observed uniformly throughout a text.

4. Abbreviations

Writers sometimes have difficulty using abbreviations because, like the rules related to numbers, guidelines that govern the use of abbreviations are often assumed rather than stated directly.

Different formatting styles involve different rules for abbreviations, so writers - especially student writers - should find out which format an instructor or course requires and follow it unwaveringly.

In general, abbreviations should be avoided in academic writing. There are, of course, key exceptions to this standard. It is permissible to use an abbreviation when it has its own dictionary definition or is otherwise commonly known.


I want to work for the IRS, but I'm not good at math.

It's also acceptable to use an abbreviation when the full phrase has been previously introduced.


The Irish Republican Army, or IRA, was most active during the late 1960s.

Latin abbreviations or reference abbreviations can also be used, as demonstrated in the following sentence:


The sources (i.e., Holmes, Catalino et al.) were used throughout the text.

Note that the above sentence is for demonstration purposes only; it's not recommended to use two abbreviations in one sentence.

In this lesson, you learned how to apply proper mechanics to your writing by investigating several common instances you may run into when drafting or revising an essay. You now have a better understanding of when and how to use capitalization and italics, the rules that govern spelling out (and not spelling out) numbers, and the acceptable use of abbreviations.

Best of luck in your learning!