What is an example of when to use a hyphen?

Using a hyphen in compound adjectives is essential to clarify the meaning of terms that are made up of two or more words when they function together as a single adjective before a noun. For example, in the phrase "a well-known author," the hyphen indicates that "well-known" is a single descriptor of "author." Without the hyphen, it may confuse the reader regarding the relationship between the words. This use ensures clarity and precision in writing.

In contrast, compound numbers typically do use hyphens, but this is less common outside specific contexts, such as when writing out numbers like "twenty-one." URLs usually do not include hyphens as they are often written as one continuous string without breaks, except in specific formatting cases. Acronyms are generally formed without hyphens since they are typically an abbreviation for longer phrases, such as "NASA" or "FBI," and do not require hyphenation for clarity.