21-letter words containing r, o, f
- catherine of braganza — 1638–1705, wife of Charles II of England, daughter of John IV of Portugal
- certificate authority — (cryptography, body) (CA or "Trusted Third Party") An entity (typically a company) that issues digital certificates to other entities (organisations or individuals) to allow them to prove their identity to others. A Certificate Authority might be an external company such as VeriSign that offers digital certificate services or they might be an internal organisation such as a corporate MIS department. The Certificate Authority's chief function is to verify the identity of entities and issue digital certificates attesting to that identity. The process uses public key cryptography to create a "network of trust". If I want to prove my identity to you, I ask a CA (who you trust to have verified my identity) to encrypt a hash of my signed key with their private key. Then you can use the CA's public key to decrypt the hash and compare it with a hash you calculate yourself. Hashes are used to decrease the amount of data that needs to be transmitted. The hash function must be cryptographically strong, e.g. MD5.
- certificate of origin — a document stating the name of the country that produced a specified shipment of goods: often required before importation of goods
- charterhouse of parma — a novel (1839) by Stendhal.
- chief warrant officer — a senior-ranking warrant officer in various armed forces
- chinese forget-me-not — an eastern Asian plant, Cynoglossum amabile, of the borage family, having lance-shaped leaves and clustered, showy, blue, pink, or white flowers.
- chloroformyl chloride — phosgene.
- circle of convergence — Mathematics. a circle associated with a given power series such that the series converges for all values of the variable inside the circle and diverges for all values outside it.
- circle of declination — hour circle.
- clement of alexandria — Saint. original name Titus Flavius Clemens. ?150–?215 ad, Greek Christian theologian: head of the catechetical school at Alexandria; teacher of Origen. Feast day: Dec 5
- clostridium difficile — Clostridium difficile is a bacterium that causes severe diarrhoea. It is commonly found in hospitals. C.diff is also used.
- college of propaganda — information, ideas, or rumors deliberately spread widely to help or harm a person, group, movement, institution, nation, etc.
- collimator viewfinder — a type of viewfinder in a camera
- collins street farmer — a businessman who invests in farms, land, etc
- come in from the cold — to come out of exile, isolation, etc.; resume an active role
- comfortably-furnished — containing comfortable furniture
- commercial fertilizer — fertilizer manufactured chemically, as distinguished from natural fertilizer, as manure.
- commission of inquiry — (in Britain) a group that is set up to investigate something
- composition of forces — the combination, by vector algebra, of two or more forces into a single equivalent force (the resultant)
- computer conferencing — the conduct of meetings through the use of computer-based telecommunications
- conference facilities — Conference facilities are large rooms and pieces of equipment that a hotel provides so an organization can have conference there.
- confirm a reservation — If you confirm a reservation, you inform someone who has booked a room at a hotel that the reservation is definite.
- confused flour beetle — a brown flour beetle, Tribolium confusum, that feeds on stored grain and grain products.
- conspiracy of silence — If there is a conspiracy of silence about something, people who know about it have agreed that they will not talk publicly about it, although it would probably be a good thing if people in general knew about it.
- continental breakfast — A continental breakfast is breakfast that consists of food such as bread, butter, jam, and a hot drink. There is no cooked food.
- correctional facility — A correctional facility is a prison or similar institution.
- cosmological redshift — the part of the redshift of celestial objects resulting from the expansion of the universe.
- counsel of perfection — excellent but unrealizable advice
- count of monte cristo — a novel (1844–45) by Alexandre Dumas père.
- court of common pleas — (formerly) a superior court exercising jurisdiction in civil actions between private citizens
- customer satisfaction — When customers are pleased with the goods or services they have bought, you can refer to customer satisfaction.
- dark-field microscope — ultramicroscope
- dataflow architecture — a means of arranging computer data processing in which operations are governed by the data present and the processing it requires rather than by a prewritten program that awaits data to be processed
- dead from the neck up — stupid or unintelligent
- defender of the faith — the title conferred upon Henry VIII by Pope Leo X in 1521 in recognition of the King's pamphlet attacking Luther's doctrines and retained by subsequent monarchs of England
- degradation of energy — the principle that during any irreversible process the total energy available to do work decreases.
- delusions of grandeur — If someone has delusions of grandeur, they think and behave as if they are much more important or powerful than they really are.
- department of defense — the department of the U.S. federal government charged with ensuring that the military capacity of the U.S. is adequate to safeguard the national security. Abbreviation: DOD.
- department of justice — the department of the U.S. federal government charged with the responsibility for the enforcement of federal laws. Abbreviation: DOJ.
- detoxification centre — a place that specializes in the treatment of alcoholism or drug addiction
- dictionary definition — the meaning of a word as given in a dictionary or dictionaries
- difference of opinion — disagreement
- differential equation — an equation involving differentials or derivatives.
- differential geometry — the branch of mathematics that deals with the application of the principles of differential and integral calculus to the study of curves and surfaces.
- differential operator — a function, usually expressed as a polynomial, that indicates linear combinations of the derivatives of the expression on which it operates.
- differential quotient — derivative (def 6).
- differential topology — the branch of topology that studies the properties of differentiable manifolds that remain invariant under diffeomorphisms.
- differential-quotient — something that has been derived.
- discriminant function — a linear function of measurements of different properties of an object or event that is used to assign the object or event to one population or another (discriminant analysis)
- distribution function — (of any random variable) the function that assigns to each number the probability that the random variable takes a value less than or equal to the given number.