- 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
- cactus dahlia ⇒ a double-flowered variety of dahlia
WordReference Random House Learner's Dictionary of American English © 2026
cac•tus /ˈkæktəs/USA pronunciation
n. [countable], pl. -ti (-tī), -tus•es, -tus.
WordReference Random House Unabridged Dictionary of American English © 2026- Plant Biologya flowering plant of hot, dry regions, with large, rounded, leafless stems usually with spines.
cac•tus
(kak′təs),USA pronunciation n., pl. -ti (-tī),USA pronunciation -tus•es, -tus.
cac′tus•like′, cac′toid, adj.
- Plant Biologyany 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.
- Greek káktos cardoon
- Latin
- 1600–10
Collins Concise English Dictionary © HarperCollins Publishers::
cactus /ˈkæktəs/ n ( pl -tuses, -ti /-taɪ/) (postpositive) Austral slang ruined, broken, or not functioning Etymology: 17th Century: from Latin: prickly plant, from Greek kaktos cardooncactaceous /kækˈteɪʃəs/ adj
'cacti' also found in these entries (note: many are not synonyms or translations):
cochineal
- prickly pear
- tuna
- barrel cactus
- chin cactus
- cholla
- epiphyllum
- hedgehog cactus
- mammillaria
- night-blooming cereus
- nopal
- peyote
- pincushion cactus
- pitahaya