Meaning & use
compound
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Meanings
nouncountablechemistry
A substance formed when two or more chemical elements join in fixed proportions.
Grammar: Takes a plural in compounds; say a compound of oxygen and hydrogen, not an element.
Patterns
- a compound of something and something
- form a compound
- an organic or inorganic compound
Water is a compound of hydrogen and oxygen.
The lab analyzed a rare compound found in the soil.
Salt is an ionic compound familiar from cooking.
nouncountable
A walled or fenced area containing a group of buildings used for one purpose.
Grammar: Usually names a protected site: enter the compound, not inside a compound element.
Patterns
- a diplomatic compound
- a military compound
- inside the compound
Visitors must show identification at the embassy compound.
The aid workers lived inside a secure compound.
Guards patrol the compound every night.
verbtransitive
To make a problem, injury, or difficulty worse by adding another cause.
Grammar: Takes an object: compound the error; the object is the thing made worse.
Patterns
- compound the problem
- compound something by doing something
- compound an error
Missing the bus only compounded my bad morning.
The company compounded the crisis by hiding the data.
A late fee can compound existing debt.
verbtransitive or intransitivetechnical
To combine parts, substances, or amounts so that they form a larger whole.
Grammar: Can take an object: compound the ingredients; or no object when parts combine: the risks compound.
Patterns
- compound ingredients
- compound risks
- compound into something
Pharmacists must compound the medicine carefully.
Small delays compounded into a major backlog.
The recipe compounds herbs, oil, and citrus peel.
adjectivebefore a nounfinancetechnical
Made of several parts, or calculated on an amount plus earlier growth.
Grammar: Comes before a noun: compound interest, not an interest is compound.
Patterns
- compound interest
- compound noun
- compound fracture
Compound interest can grow savings faster over time.
A compound noun joins two words into one idea.
The doctor treated a compound fracture.
Word forms
| plural | compounds |
|---|---|
| third person singular | compounds |
| past tense | compounded |
| past participle | compounded |
| -ing form | compounding |
Common combinations
- chemical compound
- Aspirin is a chemical compound used to reduce pain.
- compound the problem
- Deleting the backup files would only compound the problem.
- diplomatic compound
- The ambassador hosted the reception inside the diplomatic compound.
- compound interest
- The account pays compound interest monthly.
Synonyms and how they differ
- mixture
- A mixture can be physical and uneven; a compound has elements chemically joined in a fixed ratio.
- worsen
- As a verb, worsen is broader; compound suggests an extra factor making damage greater.
- complex
- Complex describes many connected parts, while compound can name a specific combined substance or site.
Opposites
Word family
- compounded adjective
- Made up of combined parts or made more serious.
- compounding noun
- The process of combining or of growth building on itself.
- component noun
- One part that helps form a whole; related in sense to combining.
Commonly confused: compound or comprise?
compound vs comprise
Comprise means consist of; compound as a noun is a combined substance, and as a verb can mean make worse.
Practice
Which sentence uses compound as a chemistry noun?
Choose one answer.
Here compound names a substance formed from elements, which matches the chemistry sense. Option 3 is also a noun, but it means an enclosed area; option 1 is the verb meaning make worse; option 4 invents a wrong banking phrase instead of compound interest.
Make it your own
Write a sentence using “compound”, then check it and compare it with the examples above.