18-letter words containing o, n, s, a
- cassini's division — the gap that divides Saturn's rings into two parts, discovered by Giovanni Domenico Cassini (1625–1712) in 1675
- 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
- cat's cry syndrome — a complex of congenital malformations in human infants caused by a chromosomal aberration and in which the infant emits a mewing cry.
- 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.
- catch one's breath — When you catch your breath while you are doing something energetic, you stop for a short time so that you can start breathing normally again.
- 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 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.
- centum call second — (unit) (CCS) A unit used (in North America) to quantify the total traffic running in a network. 1 CCS is 100 call-seconds. That means 1 CCS could be 2 calls of 50 seconds duration or 20 calls of 5 seconds duration.
- cesarean (section) — a surgical operation for delivering a baby by cutting through the mother's abdominal and uterine walls
- championship point — a point that would decide the winner of a match that would decide the championship
- change one's spots — to reform one's character
- chebyshev equation — Tchebycheff equation.
- chew someone's ear — to reprimand severely
- children of israel — the Jews; Hebrews
- 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.
- 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.
- chromatic semitone — the pitch difference between one note and its sharpened or flattened equivalent
- chronic alcoholism — long-term alcohol addiction
- chronostratigraphy — The branch of geology concerned with establishing the absolute ages of strata.
- church of scotland — the established church in Scotland, Calvinist in doctrine and Presbyterian in constitution
- cigar-store indian — a wooden statue of an American Indian, traditionally displayed at the entrance of cigar stores.
- citizen journalism — the involvement of non-professionals in reporting news, esp in blogs and other websites
- classified section — the part of a publication that contains classified advertising
- clean up one's act — to start to behave in a responsible manner
- cleopatra's needle — either of two Egyptian obelisks, originally set up at Heliopolis about 1500 bc: one was moved to the Thames Embankment, London, in 1878, the other to Central Park, New York, in 1880
- closed corporation — a corporation the stock of which is owned by a small number of persons and is rarely traded on the open market
- coals to newcastle — If someone is taking coals to Newcastle, they are trying to give or sell someone something that they already have a lot of.
- coast rhododendron — a rhododendron, Rhododendron macrophyllum, of western North America, having large clusters of rose-purple flowers spotted with brown: the state flower of Washington.
- coastguard station — the headquarters or local offices of a coastguard
- collection charges — the charges levied to cover expenses for the collection of debt
- collision coverage — Collision coverage is insurance cover for vehicle accidents.
- collision diameter — the distance between the centers of two colliding molecules when at their closest point of approach.
- colloidal solution — a mixture having particles of one component, with diameters between 10 −7 and 10 −9 metres, suspended in a continuous phase of another component. The mixture has properties between those of a solution and a fine suspension
- color transparency — a positive color image photographically produced on transparent film or glass and viewed by transmitted light, usually by projection.
- combination square — an adjustable device for carpenters, used as a try square, miter square, level, etc.
- combustion chamber — an enclosed space in which combustion takes place, such as the space above the piston in the cylinder head of an internal-combustion engine or the chambers in a gas turbine or rocket engine in which fuel and oxidant burn
- combustion furnace — a furnace used in the laboratory to carry out elemental analysis of organic compounds
- come someone's way — to come within someone's scope or range; come to someone
- comings and goings — Comings and goings refers to the way people keep arriving at and leaving a particular place.