1. Closed Form: The words are combined without a space or hyphen:
* sun + shine = sunshine
* up + grade = upgrade
2. Hyphenated Form: The words are combined with a hyphen:
* well + known = well-known
* high + school = high-school
3. Open Form: The words are combined with a space:
* real estate
* post office
Types of Compound Words:
* Noun Compounds: Two or more nouns combined to form a new noun (e.g., headache, rainbow).
* Verb Compounds: Two or more verbs combined to form a new verb (e.g., overtake, undermine).
* Adjective Compounds: Two or more adjectives combined to form a new adjective (e.g., short-sleeved, bright-eyed).
* Adverb Compounds: Two or more adverbs combined to form a new adverb (e.g., upstairs, downhill).
Examples of Compound Words:
* Bookstore
* Firefighter
* Heartbreak
* Bluebird
* Watermelon
* Crosswalk
* Weekend
* Outdoors
* Airplane
Compound words are a common feature of the English language and can be used to create new words and phrases with specific meanings. They can also be used to add emphasis or clarity to a sentence.