How To Know If A Term Is One Word Or Two Words

English loves to take existing words and smash them together so they act as one unit. This is called compounding. But how do you know if a word is one word or two?

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Question 1 of 7
Which sentence is correct?

Origin of compound

First recorded in 1350–1400; Middle English verb componen, compounen, compownen, from Old French compon- (stem of compondre ), from Latin compōnere, equivalent to com- com- + pōnere “to put”; Middle English adjective compouned, past participle of componen, as above

historical usage of compound

The English verb compound, first appearing in Middle English in the late 14th century as compounen, compownen, comes from Old French compondre, compundre “to direct, arrange,” from Latin compōnere “to put together, add together, match, match up.” The adjective compound, originally a past participle of the verb, is also recorded at the end of the 14th century. The noun, a development of the adjectival sense, is recorded considerably later, in the first half of the 16th century.
The final, unetymological -d in compound arose during the 16th century; it is of the same origin as the -d in the English word sound (meaning “noise”), which developed from the earlier English soun (from Old French son, from Latin sonus ), and the archaic verb round “to whisper,” a derivative of rune “a secret.”


Other definitions for compound (2 of 2)

[ kom-pound ]
/ ˈkɒm paʊnd /

an enclosure, especially one for prisoners.
an enclosed or protected area where a group of people live or work, such as a military base.
any separate cluster of homes, often owned by members of the same family.

Origin of compound

First recorded in 1670–80; alteration, by association with compound1, of Malay kampung “village, collection, gathering”; cf. kampong

historical usage of compound

The noun compound “a large, enclosed area” most likely comes from Malay kampong, kampung “fenced-in space, enclosure, village, a part of town inhabited by a particular nationality.” Compound originally referred to the European (originally Portuguese, Dutch, English) complexes of residences, factories, and warehouses in the East Indies, India, and China. Kampong, kampung was associated in English with the noun compound “something consisting of several parts” by 1679, when the sense “a large, enclosed area” is first recorded. The term was also used in the 19th century to describe a similar confined living area for African laborers, especially miners. By the mid-20th century, the sense of “large, walled-in space in a prison or other detention camp” first appears.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use compound in a sentence

British Dictionary definitions for compound (1 of 2)


noun (ˈkɒmpaʊnd)
verb (kəmˈpaʊnd) (mainly tr)
adjective (ˈkɒmpaʊnd)

Derived forms of compound

compoundable, adjectivecompounder, noun

Word Origin for compound

C14: from earlier compounen, from Old French compondre to collect, set in order, from Latin compōnere

British Dictionary definitions for compound (2 of 2)

/ (ˈkɒmpaʊnd) /

(esp formerly in South Africa) an enclosure, esp on the mines, containing the living quarters for Black workers
any similar enclosure, such as a camp for prisoners of war
(formerly in India, China, etc) the enclosure in which a European's house or factory stood

Word Origin for compound

C17: by folk etymology (influenced by compound 1) from Malay kampong village
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for compound

[ kŏmpound′ ]

A substance consisting of atoms or ions of two or more different elements in definite proportions joined by chemical bonds into a molecule. The elements cannot be separated by physical means. Water, for example, is a compound having two hydrogen atoms and one oxygen atom per molecule.
Composed of more than one part, as a compound eye or leaf.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for compound


In chemistry, a substance containing two or more elements in definite proportions.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.