Noun modifiers have an important job: to make nouns more expressive. Illustrated by the word "important" in the previous sentence, this type of word comes in various forms — all with a particular manner of altering the nouns attached to them. A noun modifier can come before a noun or after it. It could include complicated polysyllabic adjective phrases, or just an article like "an" or a demonstrative like "those."
A noun can have a pre-modifying noun or adjective, or it could include the noun modifier afterward. This alteration often will change the article being used. For instance, the article "an" in the phrase "an aimless sentence" changes to "a" when the modifier changes position — "a sentence that's aimless."
Another noun, several nouns or an adjective can serve as a noun modifier. It would be grammatically correct to call something "vanilla ice cream," "vanilla bean ice cream" and even "melted vanilla bean ice cream." When the modifiers come after the noun, words like "that" or "of" are added as appendages. "Melted vanilla bean ice cream" becomes "vanilla bean ice cream that's melted" or even "vanilla bean ice cream that's melted all down my wrist and onto the floor."
Punctuation often depends on how a noun is modified, with consideration to the number of modifiers and their location in the sentence. When nouns contain more than one word, they usually will not be hyphenated — as in "ice cream." In contrast, when nouns or adjectives modify another noun at the start of a phrase, they usually will take a hyphen. The phrase "ice-cream sandwich" should have a hyphen to hold the words together.
Not just articles and short phrases can serve as a noun modifier, but also long, drawn-out clauses. These chains of modifiers are held together by words like "on," "over," "from" or "of" as well as descriptors that can deliver other types of key information, for instance, "who" and "where." This is one example of a noun and its accompanying modifier: ". . . the Michelin-star chef who works in his mother's basement with two pots, a pan and a slew of family recipes."
Depending on the construction of a sentence, a noun modifier will be best-suited for location before or after a particular noun. The first time, for instance, it might be better to tell someone, "Don't touch this big red button." If the message is not successfully conveyed, the second time it might come out a little differently: "Don't touch the button that is big and red."