Compound words: Combined, Unique, Open & Closed

A compound word is a word made up of two or more smaller words that has its own unique meaning

When two smaller words combine, the new compound word has its own meaning, which can be a combined meaning, or a unique meaning

Sometimes the meanings of the smaller words provide clues to the meaning of the compound word
The meaning of the new word consists of the definitions of the smaller words
Example: "Raincoat" consists of a coat that protects the wearer from the rain
Example: "Moonlight" consists of light from the moon

Other the meanings of the smaller words do NOT provide clues that will help define the compound word
The meaning of the new word is completely unique and is not made up of definitions from the smaller words
Example: A butterfly is not flying butter; it is a flying insect
Example: Lipstick is not a stick on someone's lip; it is a makeup item

Here are some examples of compound words that are used in both writing and speaking to help describe things and clearly communicate ideas:
Mailbox
Railroad
Into
Anywhere
Basketball
Sunshine
Bathroom
Overflow
Lawsuit
Motorcycle
Bedroom
School bus
Sailboat
Honeymoon
Sandbox
Software
Mother-in-law
Check-up
Short-term
One-quarter

Closed compound words are spelled as one word, and are usually only made up of two smaller words
Example: Armchair and toothbrush

Open compound words are spelled as two words
They often consist of a modifying adjective and a noun
In open compound words, the modifying adjective does not only describe and modify the noun
Many open compound words are used together frequently, and these words take on a new meaning
The two words, although they are not joined, now form a new word with a new meaning
Example: Tennis shoes forms a new word with a new meaning
The words tennis and shoes are used together frequently to mean a pair of shoes that are used in tennis and other sports
The adjective tennis does not just describe the shoes, but it joins the word shoes to create a new word with a new meaning
Other adjectives can be used to describe shoes, but these words do not join the noun to create a new word
New shoes describe a new pair of shoes, and blue shoes describe the shoes as blue
These words do not create a new word with a new meaning when used with the word shoes
Other Examples:
High school
Real estate
Living room
School bus
Ice cream
When modifying adjectives containing the suffix -ly are used, the compound word is spelled as two words with a space between the two words
Newly married
Poorly worded

Two or more words can be joined using hyphens to create a new word with a new meaning
Typically, these words are compound adjectives, meaning that two or more adjectives are describing the same noun
Check-up
Short-term
One-quarter
Hyphenated compound adjectives come before the noun in the sentence
If the words follow the noun, they are not hyphenated
Example: It was an over-the-counter pain reliever
Example: She passed the plate over the counter
Double-digit numbers and some nouns can also be hyphenated compound words:
Thirty-five
Fifty-six
Mother-in-law

Compound words are commonly used
They can be found in conversations and writing
These questions can help when identifying compound words
Closed: Is the word made up of two or more larger words? Does this change the meaning of the new, larger word?
Open: Are these two words used together frequently? When these two words are used together, is a new meaning formed?
Hyphenated: Are two or more words joined by a hyphen to create a new meaning?

By using the questions listed above, compound words and the type of compound word can be identified
Do you like blackberries? (closed compound word: blackberries)
Visit the web page for more details. (open compound word: web page)
Please schedule a follow-up appointment. (hyphenated compound word: follow-up)
Sentences can contain more than one compound word
I love to eat peanut butter pancakes. (open compound word: peanut butter) +(closed compound word: pancakes)
Your grandmother has an old-fashioned way of doing things. (closed compound word: grandmother) + (hyphenated compound word: old-fashioned)

Spelling compound words can be difficult, but the accurate spelling of these words matters
An incorrectly spelled compound word can change the meaning of a sentence and cause miscommunication
Dictionaries ensure the correct spelling of compound words to guarantee that ideas are communicated clearly.