A cactus is a member of the plant family Cactaceae, within the order Caryophyllales. The plural of cactus varies; the Latin cacti, the English cactuses and the uninflected plural cactus are all used. Cacti have a variety of uses: some species are used as ornamental plants, others are grown for fodder or forage, others for food (particularly their fruit).
Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions. Succulent plants store water in their leaves, stems, and also in roots. Geophytes that survive unfavourable periods by dying back to underground storage organs such as tuberous roots, corms, bulbs, and rhizomes, may be regarded as succulents.