noun adjunct
noun1
Grammar, Human sciences, Linguistics, Sciences A noun that modifies another noun (thus functioning adjectivally) and that is grammatically optional; it may be a single word or a compound noun or noun phrase.
- Noun adjuncts form the first elements of hundreds of compound nouns in American English (bird house, ball field, name brand, and fieldhouse); […]1993, Kenneth G. Wilson, The Columbia Guide to Standard American English, page 300:
2
Grammar, Human sciences, Linguistics, Sciences Used other than figuratively or idiomatically: see noun, adjunct. (an adjunct to a noun)