Hyphens
Hyphens are used in English to link words together, serving various purposes like creating compound adjectives, avoiding ambiguity, and forming compound nouns. Here’s a general guide and examples to clarify when you should use a hyphen:
Compound Adjectives
When two or more words come before a noun they modify and act as a single idea, they should be hyphenated. This makes the meaning clearer.
Correct: “a two-year project” (Here, “two-year” describes the project.)
Incorrect: “a two year project” (Without the hyphen, it’s less clear that “two-year” is a single adjective.)
Correct: “a comma-separated list” (The list is separated by commas.)
Incorrect: “a comma separated list” (Without the hyphen, it could be misread as a list that is comma and separated.)
However, when the compound adjective comes after the noun, hyphens are usually not needed.
- “The project is two years long.”
- “The list is comma separated.”
Compound Nouns
Some compound nouns are hyphenated to show that the two words form a single concept.
- “mother-in-law”
- “check-in” (as in “flight check-in”)
Avoiding Ambiguity
Hyphens can help avoid ambiguity in sentences.
- “Re-sign the document” (Sign the document again) vs. “Resign from the job” (Quit the job)
- “A man-eating shark” (A shark that eats humans) vs. “A man eating shark” (A man is eating shark)
Prefixes and Suffixes
Some prefixes and suffixes may require hyphens, especially with proper nouns, or to avoid awkward letter combinations or misreading.
- “Anti-inflammatory”
- “Un-American”
- “Shell-like”
Specific Cases
- “long-standing”: Hyphenated when used as a compound adjective before a noun (“a long-standing tradition”).
- “one-period” or “two-year”: Hyphenated when used as compound adjectives before a noun.
General Rule of Thumb
- When in doubt, consult a dictionary. Usage can vary and evolve.
- Consider clarity: if a hyphen makes your sentence clearer, it’s likely beneficial.
By applying these guidelines, you should be able to resolve most hyphenation questions and make your writing clearer and more precise.
Other Examples
There should be a hyphen in “risk-adjusted probabilities.” The term “risk-adjusted” is a compound adjective describing the kind of probabilities being discussed. The hyphen clarifies that the probabilities are adjusted for risk, ensuring the phrase is read and understood correctly as a single, unified concept.
Similarly, “risk-free rate of interest” should include a hyphen, making it “risk-free rate of interest.” The hyphen connects “risk” and “free” to form a compound adjective that describes the “rate of interest.” This clarifies that the interest rate in question is free of risk.