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

At its center is a compact red source that closely resembles a little red dot and even evokes the ruby red fruit of the desert cactus.

From Science Daily ● Aug. 17, 2026

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

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

From Science Daily ● May 13, 2026

At the top of the hill stands an enormous saguaro cactus.

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

To visually take us there, it uses the headline "prickly heat", calling to mind the cacti of Arizona.

From BBC ● Jun. 26, 2026

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

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

She stood on the cacti, her feet unharmed by the prickly pears and thorns.

From "Summer of the Mariposas" by Guadalupe García McCall

The facade has vertical ridges running down the side, which Diamond said was inspired by the ribs of Saguaro cactuses.

From The Wall Street Journal ● Jul. 12, 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

Byron Jones, horticulturalist at Tacoma’s Point Defiance Zoo and Aquarium, grows a host of “unthirsty” botanical marvels in the Deserts and Baja Gardens, from sedum and cactuses to agaves and yuccas.

From Seattle Times ● Apr. 12, 2024

Pencil cactuses grew in the corners like skeleton hands.

From "The Lightning Thief" by Rick Riordan