Doesn’t it seem weird that everywhere, everyday, and everybody are singular words, but every time gets split into two? Then, some nouns, such as mother-in-law, require a hyphen. When you make a split or merge error, this means your compound either needs to get split (spaced apart) or merged (into a single word). This guide will help you learn which one to do when.
Each of the above examples falls under the category of compound, which occurs when two or more words modify each other to form a new noun or phrase. Compounds have three types: closed/solid compound words (everyday), open compounds (every time), and hyphenated compounds (mother-in-law).
Since dictionaries don’t include most temporary or recently-developed compounds, it helps to know the general patterns when you include a compound in your writing. For many compounds, writers can pick freely any of the three presentation options (like lifestyle, life-style, or life style), but in general, a writer can pick the correct option by considering if the compound functions as a noun, verb, or adjective.
Closed/Solid Compound Words
Most of the time, compound nouns become closed compound words, meaning the compound has no spaces and becomes a singular word.
Examples:
- Firefly
- Inside
- Railroad
- Basketball
- Moonlight
Additionally, compounds involving prefixes and suffixes usually become closed compound words.
Examples:
- Antisocial
- Extraordinary
- Minibike
- Midtown
- Postmodern
When prefixes and suffixes get involved, even compound adjectives typically become closed compound words.
Open Compounds
Open compounds, which include spaces between the words, typically occur when an adjective modifies a noun after it, making a more specific noun.
Examples:
- Living room
- High school
- Coffee table
- Mountain bike
- Real estate
Compound verbs typically become open compounds.
Examples:
- Take off (vs. takeoff, the noun)
- Run up (vs. runup, the noun)
- Give away (vs. giveaway, the noun)
- Hide out (vs. hideout, the noun)
- Cast away (vs. castaway, the noun)
When the compound’s describing word comes first and ends with an -ly, the compound is usually open.
Examples:
- Happily married
- Highly anticipated
- Newly formed
- Rarely mentioned
- Never forgotten
Hyphenated Compounds
Compound adjectives typically format as hyphenated compounds, with a hyphen between the words.
Examples:
- One-way street
- On-site testing
- Power-driven CEO
- Blonde-haired heartthrob
- Upside-down cake
If the compound adjective goes before the subject it modifies, then it usually stays hyphenated. However, if the compound goes after the modified subject, usually it drops the hyphen.
Examples:
- This is a one-way street. vs. This street only goes one way.
- I attended the on-site testing. vs. They held the testing on site.
Next time you wonder if you should split or merge your compound, ask yourself: is the compound a noun, verb, or adjective? Then, merge, split, or hyphenate accordingly.
