Compound Noun:

Till now we have learnt that words like cookie, cloud, tree, notebook, picture, room, etc. are nouns. Similarly, words made by a combination of two other words like classroom, doormat, grandfather, sister-in-law, ice cream, stopwatch, landlord, etc. are also nouns.

Such nouns that are made up of two or more words are known as compound nouns.

So, these are combination words. Out of the two words- one gives the idea of the general class to which the compound noun belongs. And the other tells its type within that class (this is usually known as root word). In other words, one word of a compound noun qualifies its other word.

Example:

I am looking for a marble wallpaper for my art room.
It is said, “Eat breakfast like a king, lunch like a prince and dinner like a pauper.”
The swimming pool is drained and cleaned every week.
Break-dance was a famous dance form in the nineties.

Compound nouns are made by combining either a noun, an adjective, a verb, or a preposition with another noun. After combination these are either converted to a single word or to two words that are separated with a space or two words that are separated with a hyphen.

Ø Forms of Compound Nouns→

Compound nouns are of three forms. Or we can say there are three ways of writing a compound noun: One word, Two separated words and Two words separated with a hyphen.

One word or Closed form :

watchman, blackboard, hairstylist, wallpaper, haircut, football, keyboard, spiderman.

Two words or Open form :

changing room, ice cream, dinning space, full moon, dinner table, butcher’s knife, post office.

Two words separated by hyphen or Hyphenated form :

mother-in-law, self-confidence, passer-by, six-pack, grown-up, self-esteem, self-control.

There is no proper grammar rule governing weather a compound noun will be open or closed or hyphenated. Thus, it is better to refer a dictionary to verify the form of a compound noun.

Ø Formation of Compound Nouns→

We know that compound nouns can be made by combining either a noun, an adjective, a verb, or a preposition with another noun.

Noun + Noun → Basketball, Girlfriend, Eyeballs, Airport, Petrol Pump, Riverbank.

Noun + Verb → Sunrise, Sunshine, Haircut, Thanksgiving, Rainfall, Butterfly.

Verb + Noun → Breakdance, Cookbook, Swimsuit, Breakfast, Flywheel, Washbasin.

Noun + Gerund → Windsurfing, Coal mining, Weightlifting, Kickboxing.

Gerund + Noun → Rocking Chair, Driving license, Waiting List, Running shoes.

Adjective + Noun → Highway, Gold medal, Softcopy, Blackboard, Grandmother.

Noun + Preposition → Mother-in-law, Sister-in-law, commander-in-chief, Passerby.

Preposition + Noun → Underground, Downtown, Aftermath, By- product, Upgrade.

Preposition + Verb → Bypass, Intake, Outcome, Upbringing, Outburst.

Verb + Preposition → Push-ups, Takedown, Hangover, Checkout, Cleanup.

Ø To form plural of compound nouns suffix -s is added to the root word→

In order to form the plural compound nouns the suffix -s is added to the root word or the base word. Root word is that word of the compound noun which is most significant and give meaning to the compound noun.

Examples:

SINGULAR	PLURAL
Mother-in-law	Mothers-in-law
Stepdaughter	Stepdaughters
Commander-in-chief	Commanders-in-chief
Maidservant	Maidservants
Man-of-match	Men-of-match
Cookbook	Cookbooks
Passer-by	Passers-by
Airport	Airports

Ø To form possessive case of compound noun we add apostrophe ‘s’ at the end of it→

When it comes to forming the possessive case of a compound noun, we usually face a confusion. Where to add the apostrophe ‘s’? The apostrophe ‘s’ is always added at the very end of the compound noun.

Examples:

This is my father-in-law’s
It is her stepson’s graduation ceremony.
We asked her about her sister-in-law’s
I think this is the passerby’s key, he might have dropped it here.
The kickboxer’s family is incredibly happy at his win.
All her sisters-in-law’s bungalows are in Beverly hills. (both plural and possessive case of compound noun used together)

#KEY-NOTES:

Nouns made up of combination of two or more words are called compound nouns.
Examples: Windsurfing, Waiting List, Sister-in-law, Underground, Haircut, etc.
Out of the two words- one gives the idea of the general class to which the compound noun belongs. And the other tells its type within that class.
Compound nouns are made by combining either a noun, an adjective, a verb, or a preposition with another noun.
Plural of compound nouns is formed by adding the suffix -s is added to the root word or the base word. Ex: Sisters-in-law, Swimming pools, Cookbooks, etc.
Possessive case of compound nouns is formed by adding apostrophe ‘s’ at the end. Ex: Sister-in-law’s, Spiderman’s, Policeman’s, etc.