Compound Noun: Definition, Examples & Rules | English Grammar
Last Updated: 01 Jul, 2025
Welcome! In this lesson, you'll learn everything you need to know about Compound Nouns in English grammar. We'll cover what they are, why they matter, how to form them, and how to avoid common mistakes. You'll also find real-life examples, a quick quiz, and pro tips to help you master this essential grammar topic.
What is a Compound Noun?
Compound Noun Definition: A Compound Noun is a noun made up of two or more words that together name a person, place, thing, or idea. Compound nouns can be written as one word (closed), as two words (open), or with a hyphen (hyphenated).
Why are Compound Nouns Important? They help us create new words and express complex ideas in a simple way, making our vocabulary richer and more precise.
Function in Grammar
Compound nouns are used to create new words by combining existing words. They help us name specific things, places, or concepts more efficiently. For example:
- Simple Nouns: tooth, brush, ice, cream
- Compound Nouns: toothbrush, ice cream
Compound Noun vs Simple Noun: Compound nouns combine words to create new meanings (e.g., toothbrush), while simple nouns are single words (e.g., tooth).
Compound Noun vs Simple Noun
| Simple Nouns | Compound Noun |
|---|---|
| tooth + brush | toothbrush |
| ice + cream | ice cream |
| mother + in + law | mother-in-law |
| sun + flower | sunflower |
| swimming + pool | swimming pool |
A simple noun is one word, while a compound noun combines multiple words.
Compound Noun Challenge!
Can you identify which words are compound nouns in these sentences?
- I bought a new toothbrush.
- We swam in the swimming pool.
- Her mother-in-law is visiting.
Show Answers
- toothbrush
- swimming pool
- mother-in-law
Examples of Compound Nouns in Sentences
- toothbrush (closed)
- ice cream (open)
- mother-in-law (hyphenated)
- sunflower
- swimming pool
- editor-in-chief
- blackboard
- living room
- passer-by
- notebook
Notice how each compound noun combines words to create a new meaning.
Types of Compound Nouns
- Closed Compounds: toothbrush, sunflower, notebook, blackboard (written as one word)
- Open Compounds: ice cream, living room, swimming pool, high school (written as separate words)
- Hyphenated Compounds: mother-in-law, editor-in-chief, passer-by, self-esteem (written with hyphens)
- Noun + Noun: toothbrush, sunflower, bedroom, classroom
- Adjective + Noun: blackboard, greenhouse, redhead, bluebird
- Verb + Noun: swimming pool, dining room, washing machine, reading glasses
- Preposition + Noun: underground, overcoat, underdog, outhouse
- Gerund + Noun: dining room, swimming pool, reading room, waiting room
- Self + Word: self-esteem, self-control, self-respect, self-confidence
Special Rules and Notes
- Spelling Variations: The same compound noun can be written differently in different contexts or regions. (e.g., ice cream vs ice-cream)
- Pluralization: Usually pluralize the main word. (e.g., mothers-in-law, NOT mother-in-laws)
- Possessive Forms: Add 's to the end of the compound. (e.g., mother-in-law's car, NOT mother's-in-law car)
- Meaning Changes: The meaning of a compound noun is often different from its individual parts. (e.g., "hot dog" is not a hot dog)
- Stress Pattern: Compound nouns usually have stress on the first word. (e.g., BLACKboard, not blackBOARD)
- Dictionary Check: When unsure about spelling, check a dictionary as compound nouns can vary.
Quick Quiz: Spot the Compound Noun!
Which words are compound nouns in these sentences?
- I bought a new toothbrush.
- We swam in the swimming pool.
- Her mother-in-law is visiting.
- The editor-in-chief wrote the article.
- He loves eating ice cream.
Answers: toothbrush, swimming pool, mother-in-law, editor-in-chief, ice cream
Frequently Asked Questions
What is a compound noun?
A compound noun is a noun made up of two or more words that together name a person, place, thing, or idea. They can be written as one word, two words, or with hyphens.
What are the three types of compound nouns?
The three types are: closed compounds (written as one word like "toothbrush"), open compounds (written as separate words like "ice cream"), and hyphenated compounds (written with hyphens like "mother-in-law").
How do you form plural compound nouns?
Usually pluralize the main word in the compound. For example, "mothers-in-law" (not "mother-in-laws") and "swimming pools" (not "swimmings pool").
What is the difference between a compound noun and two separate words?
A compound noun creates a new meaning different from its individual parts. For example, "blackboard" (writing surface) is different from "black board" (a board that is black).
How do you make compound nouns possessive?
Add apostrophe + s to the end of the entire compound noun. For example, "mother-in-law's car" (not "mother's-in-law car").
Can compound nouns be formed from different parts of speech?
Yes, compound nouns can be formed from various combinations like noun + noun (toothbrush), adjective + noun (blackboard), verb + noun (swimming pool), and more.
Where is the stress placed in compound nouns?
Compound nouns usually have stress on the first word. For example, "BLACKboard" (not "blackBOARD") and "TOOTHbrush" (not "toothBRUSH").
Why are compound nouns important in English?
Compound nouns help create new words and express complex ideas efficiently, making vocabulary richer and more precise while avoiding longer phrases.
Conclusion
Understanding compound nouns is key to writing and speaking English clearly and accurately. Compound nouns help you talk about specific things made up of two or more words. Always remember to use them correctly in sentences, and practice identifying them in everything you read or write. The more you practice, the easier it gets!