Hyphens Edit

Note: Highlight: Hyphenate words only when needed for clarity.

Predicate adjectives

Don’t hyphenate a predicate adjective unless specifically mentioned in the Word list and usage disctionary or otherwise. An adjective predicate is an adjective that modifies the subject of the sentence. The adjective and the subject are connected by a linking verb.

Examples

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Tip: Recommended: The image needs to be high resolution.


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Tip: Recommended: The document is up to date.

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Compound modifiers

Use hyphenated compound modifiers before a noun. A compound modifier (also known as a noun modifier) precede and modify the noun as a unit. Only hyphenate two or more words that precede and modify the noun as a unit of it doesn’t result in undue confusion. Don’t hyphenate a compound modifier when you use it after a noun.

Examples

Warning: Not recommended: Don’t use the recently deprecated tool.


Tip: Recommended: Don’t use the recently-deprecated tool.


Warning: Not recommended: The high capacity website hosting is impressive.


Tip: Recommended: The high-capacity website hosting is impressive.

Hyphenate two or more words that precede and modify the noun:

  • If one of the words is a past or present participle (a verb ending in -ing or -ed being used as an adjective or noun).
    • For example, well-formatted text, mind-stimulating blog, or left-aligned paragraph.
  • If the compound modifier is a number or a single letter with a noun or participle.
    • For example, three-pronged approach, Cartesian x-axis, or 4-sided quadrilateral.

In compound words that precede and modify a noun as a unit, don’t hyphenate:

  • The word very when it precedes another modifier.
    • For example, very high capacity or very fast storage.
  • Adverbs ending in -ly when they precede another modifier. Don’t hyphenate adverbs unless absolutely needed for clarity. If you’re doubtful of a particular word being an adverb, first refer the Word list and usage dictionary; if it’s not covered there, refer the American Heritage Dictionary and Merriam-Webster.
    • For example, highly intensive processing or readily available source code.

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Compound words

When two or more words are joined to form a new word, it is called a compound word. Hyphenate compound nouns when one of the words is abbreviated.

Examples

  • e-learning
  • e-commerce

To determine if a particular word can be hyphenated or not, refer the Word list and usage dictionary. If you’re doubtful of a particular word, and if it’s not covered in the Word list and usage dictionary, refer the American Heritage Dictionary and Merriam-Webster.

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Numbers and fractions

Hyphenate compound numerals and fractions.

Examples

  • Jump to the thirty-second page in the user manual.
  • Split the columns into one-thirds using the column block.

En dashes (–) are generally used to indicate a range of numbers, the minus sign, or negative numbers. Although you can use en dashes for these purposes, you can also use hyphens or the word to for numerical ranges. Use an en dash indicate a range of numbers such as values or dates. Don’t add spaces before and after the en dash or the hyphen. Use an en dash instead of a hyphen in a compound adjective when the compound adjective includes an open compound.

For more information, see En dashes, Range of numbers, and Range of numbers with units.

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Prefixes and suffixes

Avoid creating new words by adding prefixes or suffixes to existing words. Rewrite the word to avoid creating a new word, so as to prevent any confusion.

Don’t hyphenate a word that has a prefix or suffix, in the following situations:

  • After these prefixes: auto-, co-, cyber-, exa-, giga-, kilo-, mega-, micro-, non-, pre-, re-, sub-, tera-, un- unless excluding it could cause confusion.

Hyphenate a word that has a prefix or suffix, in the following situations:

  • When not hyphenating results in a confusing word; for example, non-native, re-count, re-mark.
  • When a number or a capital letter follows the prefix; for example, non-English, pre-2000.
  • When the prefix is self-; for example, self-diagnosis, self-exclusion.
  • When the prefix is followed by a word that is already hyphenated.
  • When the prefix ends in a vowel, and the word it precedes starts with the same vowel; for example, co-operate, anti-immune, re-establish. [review]
  • When the prefix is followed by a compound word that contains a space. In this case, the space is replaced with a hyphen; for example, world wide web but pre-world-wide-web media.

For more information, see Prefixes and suffixes.

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Space around hyphens

Don’t insert a space on either side of a hyphen, except when using a suspended hyphen, in which case insert a space after (but not before) the hyphen.

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Suspended hyphens

Don’t use suspended compound modifiers that have a common base. You can either spell out the entire phrase, or leave a space after hyphen and leave out the base. Don’t form suspended compound modifiers from one-word adjectives.

Examples

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Tip: Recommended: You can use either left-aligned, right-aligned, or center-aligned text formatting.


Tip: Recommended: You can use either left-, right-, or center-aligned text formatting.

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Capitalization in hyphenated compound words

Capitalize any part of a hyphenated compound word even if it isn’t capitalized without a hyphen.

Examples

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Tip: Recommended: Well-formatted text is a vital element to enhance readability.

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Additional resources

Don’t use hyphens and dashes interchangeably. For more information, see Dashes.

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