A noun is a person, place, thing, idea, quality, or event. There are different types of a noun like Common noun, Proper noun, Abstract noun, Concrete noun, collective noun, countable noun, Non-countable noun, Compound noun, etc.
Compound nouns contain two or more words that join together to make a single word. A compound noun is a type of noun that is used to designate a person, place, or thing. Compound nouns are formed in three-way which includes:
1. The closed-form in which two forms are simply put together to form one single word.
2. The hyphenated form, these are compound noun connect two or more with or more hyphens between them
3. The open form, these are compound nouns that function as one unique word but are still as two or more separate words.