Here are some examples of hyphenated nouns:
* Compound adjectives: These are often used to describe something, such as "a well-known author" or "a state-of-the-art facility."
* Fractions: Hyphens are used to indicate fractions, such as "one-third" or "two-fifths."
* Numbers: When writing numbers, hyphenate them between twenty-one and ninety-nine, such as "forty-two" or "seventy-five."
* Combinations of words: Some nouns are formed by combining two words, such as "mother-in-law" or "brother-in-law."
* Directional terms: These are often used to describe location, such as "south-west" or "north-east."
The use of hyphens in compound nouns can vary depending on the specific words being combined, and there are some general rules to follow:
* Use a hyphen when the words together create a new concept. For example, "a high-speed train" is a different kind of train than a "high speed" train.
* Use a hyphen when the words are modifying a noun together. For example, "a well-known author" is a different kind of author than "a well known author."
* Use a hyphen when the words are likely to be misunderstood without it. For example, "a three-year-old child" is different from "a three year old child."
It's important to note that hyphenation rules can be complex, and there are often exceptions. Consulting a style guide or dictionary can be helpful for resolving any uncertainties.