cactus

American  

[kak-tuhs] / ˈkæk təs /

noun

cacti, plural cactuses, plural cactus plural

1. any of numerous succulent plants of the family Cactaceae, of warm, arid regions of the New World, having fleshy, leafless, usually spiny stems, and typically having solitary, showy flowers.

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cactus British  

/ kækˈteɪʃəs, ˈkæktəs /

noun

1. 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

2. a double-flowered variety of dahlia

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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

Derived Forms

• cactaceous
  adjective
• cactoid
  adjective
• cactuslike
  adjective

Inflected Forms

Nouns

• cacti
  plural
• cactus
  plural
• cactuses
  plural

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.

Example Sentences

See Examples For:

cactus cacti cactuses

She has a piece with prickly pear cactus as well as datura in it, which is crazy.

From Los Angeles Times ● Jun. 17, 2026

For him and his fellow farmers the agave cactus was just a "stubborn, valueless weed" - planted as fencing to keep wild animals off their crops.

From BBC ● Jun. 11, 2026

Anna brought Sutskever a cactus as a final offering.

From The Wall Street Journal ● May 30, 2026

The research team analyzed flower length data from more than 750 cactus species.

From Science Daily ● May 13, 2026

“I’d never seen a saguaro cactus until I moved here,” I told them, thinking of the great saguaro at the top of my hill.

From "Insignificant Events in the Life of a Cactus" by Dusti Bowling

New research shows that cacti are remarkably quick at forming entirely new species, revealing that deserts are far more dynamic than they may seem.

From Science Daily ● May 13, 2026

The streets of the Catalina Foothills are lined with Arizona's iconic, giant three-armed Saguaro cacti – and throngs of journalists, investigators and neighbours fixated on the disappearance of the mother of TV presenter Savannah Guthrie.

From BBC ● Feb. 7, 2026

For others, like cacti and succulents, Clare says we mistakenly drown them by unnecessarily watering them.

From BBC ● Jan. 14, 2026

Inside, the gardens are divided into houses highlighting different plants and climates — from the Palm House with over 70 palms, to the fern room, to the desert house filled with cacti and succulents.

From Salon ● Sep. 29, 2025

Some of the cacti or prickly pears escaped from his gardens and by 1925 about 20 species could be found growing wild.

From "Silent Spring" by Rachel Carson

Velvet-coated sculptures of cactuses and otherworldly beaded plants provide some of the much needed levity that the show so hopes to achieve.

From The Wall Street Journal ● Jul. 24, 2026

Among the cactuses in the desert of Arizona, just outside Phoenix, an extraordinary collection of buildings is emerging that will shape the future of the global economy and the world.

From BBC ● May 18, 2025

After a few hours of falling down into desert washes and getting spiked by cactuses, the group realized they were in trouble.

From Salon ● Oct. 4, 2024

In describing the cactuses and the palm trees, he notes “the laciness of it all. … It has a magic to it that attracted me.”

From Los Angeles Times ● Aug. 7, 2024

We had all seen the clumps of prickly pear cactuses that were growing everywhere.

From "Code Talker: A Novel About the Navajo Marines of World War Two" by Joseph Bruchac