Compound nouns are those nouns which consist of two (wallpaper, blackboard), three (brother-in-law) or more parts. Such parts can be two nouns (e.g. wallpaper, raincoat), a noun with a verb (e.g. typewriter) as well as an adjective with a noun (e.g. blackboard).
It also quite common to see the gerund form (-ing) connected to a noun, as in a frying pan, a dining-room or a noun with the gerund form (e.g sightseeing). Some nouns can be used as an adjective:
- a car key
- a toy shop
- a table leg