cactus

American  

[kak-tuhs] / ˈkæk təs /

noun

plural

cacti, cactuses, cactus

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

• cactaceous adjective
• cactoid adjective
• cactuslike adjective

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

The film cuts to a hummingbird sipping nectar from a flower on a cactus, a sea turtle floating over a coral reef, pink flamingos on a green lake, a snowflake, a butterfly.

From The Wall Street Journal • Apr. 16, 2026

One is the charming pueblo in foothills lined with neat rows of agave cactus.

From Los Angeles Times • Mar. 6, 2026

Bezos and Sanchez have placed the sauna, which is understood to have been designed by Timothy Oulton Studio, near the cactus garden.

From MarketWatch • Dec. 26, 2025

Elsewhere, a noble is a fair dinkum, while the death of an important character is announced by "he's cactus".

From BBC • Nov. 14, 2025

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