What does compound mean?
A compound is fundamentally a thing made by joining two or more distinct parts into a single whole, and the idea shows up everywhere in English. In chemistry, a compound is a substance formed when two or more elements bond chemically — water, made of hydrogen and oxygen, is the classic example. In grammar and linguistics, compounds are words built from two or more smaller words, like 'notebook' or 'sunflower'. In finance, compound interest refers to growth that accumulates on both the original amount and previously earned interest. As a verb, 'to compound' most commonly means to make a bad situation worse, as in 'his silence compounded the misunderstanding', though it can also mean to combine or accumulate. The noun can even describe an enclosed cluster of buildings, as at a military compound. Versatile and precise, the word belongs to the core vocabulary of science, law, language, and everyday reasoning alike.
A thing formed by combining two or more parts, especially a chemical substance consisting of atoms of different elements bonded together.
"Carbon dioxide is a compound of carbon and oxygen."
In everyday use, 'compound' can refer more loosely to any mixture or combination, though chemists reserve it strictly for substances with fixed chemical bonds.
To make a problem, difficulty, or mistake worse by adding to it; also, to combine or accumulate, as in compounding interest.
"The company's delays compounded the supply chain crisis."
Stressed on the second syllable (/kəmˈpaʊnd/), unlike the noun.
Composed or consisting of two or more parts, elements, or words joined together.
"'Notebook' is a compound word made from 'note' and 'book'."
Standard pluralization applies. In chemistry, 'compounds' refers to multiple distinct chemical substances; in linguistics, it refers to multiple compound words.
"Organic chemistry studies thousands of carbon-based compounds."
The same word that describes water in your glass also describes how debt quietly grows against you — compound interest is why small loans can become enormous ones.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of compound
Compound derives from the Latin verb 'componere', meaning 'to put together', formed from the prefix 'com-' ('together') and 'ponere' ('to place'). The word entered English in the late Middle Ages through Old French forms related to composing and combining. It shares its Latin root with a family of English words including compose, component, composite, position, and postpone, all ultimately tracing back to the act of placing or putting. The stress difference between the noun and verb reflects an older pattern in English borrowed vocabulary.
Related word forms
How compound is actually used
Note the shift in stress between the noun/adjective (/ˈkɒmpaʊnd/) and the verb (/kəmˈpaʊnd/) — this stress alternation follows a common English pattern. The verb 'to compound' meaning 'to worsen' carries a negative connotation, while the noun is neutral across scientific, linguistic, financial, and everyday contexts. In finance and law, 'compounded' often implies accumulation over time.
Easily confused with compound
Compost is decayed organic matter used as fertilizer, whereas a compound is any combination of two or more parts into a unified whole.