cactus
Americannoun
plural
cacti, cactuses, cactusnoun
-
any spiny succulent plant of the family Cactaceae of the arid regions of America. Cactuses have swollen tough stems, leaves reduced to spines or scales, and often large brightly coloured flowers
-
a double-flowered variety of dahlia
Usage
Plural word for cactus The plural form of cactus can be either cacti, cactuses, or cactus. Cacti is most commonly used. Like many words derived from Latin, it is pluralized by replacing the -us ending with -i, as in fungus/fungi and nucleus/nuclei. However, the plural form cactuses, created by adding the typical -es to the end, is also correct. This alternative plural form is also acceptable for some other Latin-derived or related terms, as in focus/foci/focuses and radius/radii/radiuses.
Other Word Forms
Etymology
Origin of cactus
1600–10; < Latin < Greek káktos cardoon
Explanation
A cactus is a succulent desert plant that's often covered in sharp spines. Some cacti grow brilliantly colored flowers, but none of them have leaves. You can grow an indoor cactus in a pot — it's a fairly easy plant to care for, since it prefers to be watered infrequently. Cacti are able to conserve water, which is why they do well in very dry environments, like the American Southwest. The Greek root of cactus is kaktos, the name of a specific spiky Sicilian plant.
Vocabulary lists containing cactus
This Week in Words: Current Events Vocab for April 16–April 22, 2022
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This Week in Words: Current Events Vocab for May 22–May 28, 2021
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
With nearly one-third of cactus species currently threatened with extinction, researchers say the database will provide an important tool for studying how these plants may respond to climate change in the future.
From Science Daily • May 13, 2026
Aside from a cactus he waters once a month, he’s alone.
From The Wall Street Journal • Apr. 27, 2026
It takes in the affluent enclaves of Scottsdale and Paradise Valley and — where the urban sprawl finally yields to cactus, palo verde and other flora — Carefree and the Old West-themed Cave Creek.
From Los Angeles Times • Feb. 15, 2026
The video for Opalite premiered on Friday, and stars Irish actor Domhnall Gleeson as a "lonely man" who summons Swift into his life by spraying a magic potion on his beloved cactus.
From BBC • Feb. 6, 2026
Professor McGonagall barked at the end of one particularly difficult lesson, during which Neville had accidentally transplanted his own ears onto a cactus.
From "Harry Potter And The Goblet Of Fire" by J. K. Rowling
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.