18-letter words containing s, i, o
- cabernet sauvignon — a black grape originally grown in the Bordeaux area of France, and now throughout the wine-producing world
- california fuchsia — a North American onagraceous plant, Zauschneria californica, with tubular scarlet flowers
- california rosebay — a Pacific coast shrub or tree (Rhododendron californicum) of the heath family, with rosy or purplish flowers
- california-fuchsia — a plant belonging to the genus Fuchsia, of the evening primrose family, including many varieties cultivated for their handsome drooping flowers.
- call into question — to raise a question or doubt about
- calliper compasses — an instrument for measuring internal or external dimensions, consisting of two steel legs hinged together
- cambrian mountains — a mountain range in Wales, extending from Carmarthenshire in the S to Denbighshire in the N. Highest peak: Aran Fawddwy, 891 m (2970 ft)
- camp david accords — a peace treaty between Israel and Egypt issuing from talks at Camp David between Egyptian President Sadat, Israeli Prime Minister Begin, and the host, U.S. President Carter: signed in 1979.
- can stick/to stick — If you say that someone can stick something, especially a job, or if you tell them where to stick it, you are rudely refusing it or emphasizing that you do not want it or like it.
- cape breton island — an island off SE Canada, in NE Nova Scotia, separated from the mainland by the Strait of Canso: its easternmost point is Cape Breton. Pop: 132 298 (2006). Area: 10 280 sq km (3970 sq miles)
- capital allowances — the money spent by a company on fixed assets which can be taken off the profits of the company before tax is imposed
- captain james cook — Frederick Albert, 1865–1940, U.S. physician and polar explorer.
- carbonic anhydrase — an enzyme in blood cells that catalyses the decomposition of carbonic acid into carbon dioxide and water, facilitating the transport of carbon dioxide from the tissues to the lungs
- carcinoid syndrome — the systemic effects, including flushing, palpitations, diarrhea, and cramps, resulting from increased blood levels of serotonin secreted by a carcinoid.
- carisbrooke castle — a castle near Newport on the Isle of Wight: Charles I was held prisoner here from 1647 until his execution in 1649
- carolina jessamine — a vine, Gelsemium sempervirens, of the southern U.S. and Central America, of the logania family, having glossy, lance-shaped leaves and fragrant yellow flowers: the state flower of South Carolina.
- cartilaginous fish — any fish of the class Chondrichthyes, including the sharks, skates, and rays, having a skeleton composed entirely of cartilage
- cash-for-questions — of, involved in, or relating to a scandal in which some MPs were accused of accepting bribes to ask particular questions in Parliament
- cassini's division — the gap that divides Saturn's rings into two parts, discovered by Giovanni Domenico Cassini (1625–1712) in 1675
- cassiopeia's chair — the five brightest stars in the constellation Cassiopeia that seem to form the shape of a W or M
- cassius (longinus) — (Gaius)died 42 b.c.; Rom. general & conspirator against Caesar
- castration complex — an unconscious fear of having one's genitals removed, as a punishment for wishing to have sex with a parent
- catalogue raisonne — a descriptive catalogue, esp one covering works of art in an exhibition or collection
- catalonian jasmine — a shrub, Jasminum grandiflorum, of India, having crimson-tinged, fragrant white flowers, grown as an ornamental and for perfume.
- catherine of siena — Saint. 1347–80, Italian mystic and ascetic; patron saint of the Dominican order. Feast day: April 29
- catskill mountains — a mountain range in SE New York State: resort. Highest peak: Slide Mountain, 1261 m (4204 ft)
- caucasus mountains — a mountain range in SW Russia, running along the N borders of Georgia and Azerbaijan, between the Black Sea and the Caspian Sea: mostly over 2700 m (9000 ft). Highest peak: Mount Elbrus, 5642 m (18 510 ft)
- cauliflower cheese — a dish of cauliflower with a cheese sauce, eaten hot
- cauliflower fungus — a large edible white to yellowish cauliflowerlike mushroom, Sparassis radicata, widely distributed in North America.
- causa sine qua non — an indispensable condition; requisite.
- centralized school — a public school formed from the pupils and teachers of a number of discontinued smaller schools, especially in a rural district.
- cesarean (section) — a surgical operation for delivering a baby by cutting through the mother's abdominal and uterine walls
- chagos archipelago — group of islands in the Indian Ocean 1,180 mi (1,899 km) northeast of Mauritius, comprising the British Indian Ocean Territory: chief island, Diego Garcia
- championship point — a point that would decide the winner of a match that would decide the championship
- character disorder — a disorder characterized by socially undesirable behavior, as poor control of impulses or inability to maintain close emotional relationships, and by absence of anxiety or guilt.
- chebyshev equation — Tchebycheff equation.
- child psychologist — a psychologist who specializes in treating children
- children of israel — the Jews; Hebrews
- chinese gooseberry — kiwi (sense 2)
- chinese revolution — the overthrow of the last Manchu emperor and the establishment of a republic in China (1911–12)
- chinese watermelon — a tropical Asian vine, Benincasa hispida, of the gourd family, having a brown, hairy stem, large, solitary, yellow flowers, and white, melonlike fruit.
- chord of the sixth — sixth chord.
- chrétien de troyes — 12th century, French poet, who wrote the five Arthurian romances Erec; Cligès; Lancelot, le chevalier de la charette; Yvain, le chevalier au lion; and Perceval, le conte del Graal (?1155–?1190), the first courtly romances
- christian brothers — a religious congregation of laymen founded in France in 1684 for the education of the poor
- christian democrat — a member or supporter of a Christian Democratic party
- christian endeavor — an organization of young people of various evangelical Protestant churches, formed in 1881 to promote Christian principles and service.
- christian reformed — of or relating to a Protestant denomination (Christian Reformed Church) organized in the U.S. in 1857 by groups that had seceded from the Dutch Reformed Church.
- christmas shopping — shopping especially for Christmas presents, but also for Christmas food and drink, and all the other things required over the Christmas period.
- christmas stocking — A Christmas stocking is a long sock which children hang up on Christmas Eve. During the night, parents fill the stocking with small presents.
- christopher sholes — Christopher Latham [ley-thuh m,, -th uh m] /ˈleɪ θəm,, -ðəm/ (Show IPA), 1819–90, U.S. inventor of the typewriter.