What does cactus mean?
A cactus is a spiny, succulent plant belonging to the family Cactaceae, native almost entirely to the Americas and superbly adapted to hot, dry environments. Instead of broad leaves, most cacti have thick, fleshy stems that store water, allowing them to survive long droughts, and their leaves have evolved into spines that reduce water loss and deter animals. The word covers everything from tiny button-sized species to the towering saguaro of the Sonoran Desert. In everyday use, 'cactus' appears in gardening, interior design (potted cacti are prized as low-maintenance houseplants), and desert landscapes. The plural is a small point of style: 'cacti' reflects the word's Latin origin, while 'cactuses' is equally correct and more colloquial. Figuratively, the cactus has come to suggest resilience and self-sufficiency — something that thrives where little else can — making it a durable symbol of endurance in art, literature, and popular culture.
nounA spiny, usually succulent plant of the family Cactaceae, native chiefly to arid regions of the Americas, with thick fleshy stems adapted to store water and typically lacking true leaves.
- A spiny succulent plant of the family Cactaceae, native to the Americas, with fleshy water-storing stems.
- (Informal, rare) Any similar spiny or thorny plant by loose association.
"The desert hillside was covered with saguaro and prickly pear cactus."
"She kept a small potted cactus on her desk because it needed almost no attention."
"The trail wound through a landscape of towering saguaro cactus under a blazing sun."
'Cacti' preserves the Latin plural and is traditional in scientific and formal writing; 'cactuses' is fully standard and often preferred in general prose. Both are widely accepted, though some style guides favor one consistently.
"The greenhouse displayed dozens of flowering cacti from the Atacama Desert."
A cactus can survive years without rain — one specimen famously outlived its own owner's house.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cactus
The word 'cactus' comes directly from Latin, where it denoted a spiny plant — likely the cardoon or a similar thistle-like artichoke relative rather than the American plants we now call cacti. Latin probably adopted the term from Greek 'kaktos', used by writers such as Theophrastus for a prickly Mediterranean plant. When European botanists encountered the unfamiliar succulent plants of the Americas in the early modern period, they applied the classical name to them, fixing 'cactus' as the scientific genus name (Linnaeus established Cactus as a genus in the 18th century) and hence as the ordinary English word. The botanical family name Cactaceae derives from the same root.
Related word forms
How cactus is actually used
The plural is contested: 'cacti' follows the Latin original and remains common in careful or scientific writing, while 'cactuses' is fully standard in everyday English; both are widely accepted. The informal collective term 'cactus' for the group of plants is normal in botany. In casual British slang, 'cactus' can describe something broken or ruined ('my phone's gone cactus'), an Australian/NZ usage worth noting but not standard elsewhere.
Easily confused with cactus
A succulent is any water-storing plant (including many non-cacti such as aloes and echeverias), whereas a cactus specifically belongs to the family Cactaceae.