Noun modifier
From Teflpedia
A noun modifier, noun adjunct or attributive noun is a noun that is used as a modifier on another noun.[1]
For example, in the phrase "tomato soup", tomato is a noun modifier.
Note that the modifier is usually singular, even if the word is usually plural, e.g. trouser in "trouser leg".
This results in a compound noun, which may be compounded into one word, hyphenated, or spelt as two (or more) words.
