What is a compound noun?
A compound noun is a noun that is made up of two or more words. Most compound nouns in English are formed by nouns modified by other nouns or adjectives.
1.The words tooth and paste are each nouns in their own right, but if you join them together they form a new word - toothpaste.
2.The word black is an adjective and board is a noun, but if you join them together they form a new word - blackboard.
In both these example the first word modifies or describes the second word, telling us what kind of object or person it is, or what its purpose is. And the second part identifies the object or person in question.
Types of compound nouns
1.The "closed (solid)" forms in which two usually moderately short words appear together as one. Solid compounds most likely consist of short (monosyllabic) units that often have been established in the language for a long time.
Barmaid, Bathroom, Breakdown, Buttermilk, and Butterscotch
2.The hyphenated form in which two or more words are connected by a hyphen. Compounds that contain affixes, such as house-build(er) and single-mind(ed)(ness), as well as adjective-adjective compounds and verb-verb compounds, such as blue-green and freeze-dry, are often hyphenated. Compounds that contain articles, prepositions or conjunctions, such as rent-a-cop, mother-of-pearl and salt-and-pepper, are also often hyphenated.
Air-brake, Baby-sitter, Daughter-in-law, Editor-in-chief, Master-at-arms, Over-the-counter, White-wash
3.The open (spaced) form consisting of newer combinations of usually longer words, such as distance learning, player piano, lawn tennis, etc.
Attorney general, Fish tank, Half sister, Post office, Real estate, and Middle class.
The list of compound nouns
grant- in - aid
attorney- at- law
mother- in- law
jack- in- the- box
sergeant- at- arms
master- at- arms
SEPARATED/ OPEN FORM