9 of the Most Important English Capitalization Rules

English capitalization refers to the practice of adding capital (uppercase) letters to words in sentences, subheadings, and titles, where you should include them. When to capitalize words, and when not to capitalize them, that is the question.

(10 Most Important Comma Usage Rules.)

Numerous English rules govern when we must capitalize words in articles or books. Although the more basic capitalization rules are relatively clear-cut, confusion can still sometimes arise about when to capitalize words in certain circumstances. These are the most important English capitalization rules to abide by. 

The most basic capitalization rule is that the first words in sentences must always start with capital letters. That is perhaps the strictest and most universal capitalization rule for which there is no exception. There's not much more that can be said about this rule, except perhaps not to confuse semicolons to be the same as full stops (periods). You should not usually capitalize the first word after a semicolon (unless it's a proper noun, formal title, or abbreviation) because it doesn't start a new sentence like a period does.

A proper noun is a specific name for a person, place, or thing. The general capitalization rule for proper nouns is that the first letters in their words must be capitalized. These are some examples of capitalized proper nouns:

The principal words in proper nouns, like those above, should be capitalized. Exceptions are made for conjunctions (such as and, but, or, etc.) and short prepositions (in, at, on, to, for, by, etc.) included within the proper nouns. Thus, the preposition in the Church of England is not capitalized.

However, the capitalization of proper nouns is more of a general rule (rather than a strict one) because of the increasing number of companies releasing products with names that don't start with uppercase letters. Apple is perhaps the most guilty culprit of expanding this rising (and frankly unwelcome) lowercase marketing trend with its iPhone, iPad, iMac, iPod, and macOS products. Those proper nouns for some Apple products have unique and awkward capitalization. When it comes to products, we must capitalize them exactly as Apple and company do on their websites and marketing materials.

Another point to note is that general food and drink names are common nouns rather than proper ones. Thus, food names like banana, tea, cheese, apple, milk, chocolate, chips, sandwich, and crisps should not be capitalized. However, brand names for foods should be capitalized, such as Tabasco sauce, Hellman's mayonnaise, Cadbury's Dairy Milk, and Heinz Tomato Ketchup.

A derivative is a word formed from another word. The many derivatives of proper nouns should always be capitalized in much the same way. For example, Russian, Christian, Germanic, and Venetian are capitalized derivatives for Russia, Christianity, German, and Venice.

I is a personal pronoun, which refers to I, myself, that must always be capitalized. That is the only pronoun we must always capitalize because of its unique single-letter nature. So, don't forget to press the Shift key when entering the I pronoun in articles with a first-person narrative.

English capitalization rules for titles and subheadings can be more confusing because alternative style guides (such as The Associated Press Stylebook and The Chicago Manual of Style) have slightly different conventions for them. The general rule is that nouns, pronouns, adjectives, verbs, and adverbs in titles should have capital letters. It is not necessary to capitalize coordinate conjunctions (and, but, for, etc), articles (an, the, a), and shorter propositions in titles. That is the traditional title case rule for capitalizing the principal words in headings.

These are some examples of title case headings:

Yet, the rules for title and subheading capitalization are slightly loose, with different style guides having variable preferences. If you prefer Associated Press, then stick to that style guide for your titles. Or, you can capitalize titles and subheadings in your articles according to the Chicago Manual. Capitalization consistency is most important for titles and subheadings. You can utilize this Title Case Converter online tool to ensure heading and subheading capitalization consistency for your preferred style.

Words like president, director, king, pope, and doctor are common nouns that should not have capital letters when they stand alone. However, this changes when formal titles directly precede proper noun names. Formal titles must be capitalized when preceding person names, as in these examples:

Historical eras were notable periods that had significant changes and events. The historical events were typically wars, but can also be other significant revolutionary, economic, or social occurrences in history. We should always capitalize specifically named historic eras and events, such as the following:

Abbreviations are shortened forms of words that should be capitalized when used for abbreviated titles. For example, Mr. and Ms. are two common title abbreviations for mister and miss that are always capitalized when standing alone or preceding surnames. Jan., Feb., Mar., and Apr. are abbreviations capitalized like their full month names, January, February, March, and April. However, we don't capitalize Latin abbreviations such as e.g. (for example), etc. (for et cetera, which translates to the rest), and i.e. (for that is).

An acronym is a special type of abbreviation that's a pronounceable word formed from a longer phrase or proper noun. For example, NATO (North Atlantic Treaty Organization), NASA (National Aeronautics and Space Administration), JPEG (Joint Photographic Expert Group), UAP (Unidentified Anomalous Phenomena), and RAM (Random Access Memory) are some common acronyms. Such acronyms should be fully capitalized with all uppercase letters, like the preceding examples in this passage.

Quotations are frequently used in the middle of sentences. When quoting any complete sentence, you must always start the quotation with a capital letter, even from mid-sentence. However, we can make exceptions for partial quotes that are not full sentences. Here are a few examples of full and partial quotes:

So, don't forget those most significant English capitalization rules for your articles or books. We must abide by those rules of capitalization because they help readers identify proper nouns, the I pronoun, abbreviations, and title headings. Correct capitalization will also enhance clarity and consistency in your articles, books, letters, emails, and other documents.