19-letter words containing r, d, o
- saber-toothed tiger — any of several extinct members of the cat family Felidae from the Oligocene to Pleistocene Epochs, having greatly elongated, saberlike upper canine teeth.
- sabre-toothed tiger — any of various extinct Tertiary felines of the genus Smilodon and related genera, with long curved upper canine teeth
- saccharolactic acid — mucic acid.
- saddle-billed stork — a large stork, Ephippiorhynchus senegalensis, of West Africa, having a white and black body and a long, red and black bill.
- samoa standard time — a standard time used in the zone which includes American Samoa, corresponding to the mean solar time of the 165th meridian west of Greenwich, England: it is eleven hours behind Greenwich time
- san bernardino pass — a pass over the Lepontine Alps in SE Switzerland. Highest point: 2062 m (6766 ft)
- san fernando valley — valley in SW Calif., partly in NW Los Angeles: c. 260 sq mi (673 sq km)
- san salvador island — an island in the central Bahamas: the first land in the New World seen by Christopher Columbus (1492). Area: 156 sq km (60 sq miles)
- sandra day o'connor — Frank (Michael Donovan) 1903–66, Irish writer.
- sandwich generation — the generation of people still raising their children while having to care for their aging parents.
- santa rosa de copan — a town in W Honduras: site of extensive Mayan ruins.
- santiago del estero — a city in N Argentina.
- scale down (or up) — to reduce (or increase), often according to a fixed ratio or proportion
- screen actors guild — a labor union for motion-picture performers, founded in 1933. Abbreviation: SAG.
- sea floor spreading — a process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out.
- sea-floor spreading — a process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out.
- secondary dentition — the permanent dentition
- secondary education — education at high-school level
- secondary infection — an infection resulting from another infection
- secondary intention — See under intention (def 5b).
- secondary picketing — the picketing by strikers of a place of work that supplies goods to or distributes goods from their employer
- secondary processes — the conscious mental activity and logical thinking controlled by the ego and influenced by environmental demands.
- secondary qualities — one of the qualities attributed by the mind to an object perceived, such as color, temperature, or taste.
- secondary structure — the arrangement of a polypeptide into a regular alpha helix, beta structure, or random coil configuration by the formation of intramolecular hydrogen bonds along the length of the chain.
- secondary-intention — an act or instance of determining mentally upon some action or result.
- self-administration — the management of any office, business, or organization; direction.
- self-discrimination — an act or instance of discriminating, or of making a distinction.
- sell down the river — a natural stream of water of fairly large size flowing in a definite course or channel or series of diverging and converging channels.
- semiconductor laser — a laser in which a semiconductor is the light-emitting source, used in many medical procedures.
- semipalmated plover — a New World plover, Charadrius semipalmatus, having a black ring around the chest and semipalmate feet, inhabiting beaches and salt marshes.
- senatorial district — one of a fixed number of districts into which a state of the U.S. is divided, each electing one member to the state senate.
- sensory deprivation — the experimental or natural reduction of environmental stimuli, as by physical isolation or loss of eyesight, often leading to cognitive, perceptual, or behavioral changes, as disorientation, delusions, or panic.
- sexual reproduction — reproduction involving the union of gametes.
- sharp-tailed grouse — a grouse, Pedioecetes phasianellus, of prairies and open forests of western North America, similar in size to the prairie chicken but with a more pointed tail.
- sheet flood erosion — Geology. erosion by sheets of running water, rather than by streams.
- ship-to-shore radio — a radio that carries communications between land and sea
- sidereal hour angle — the angle, measured westward through 360°, between the hour circle passing through the vernal equinox and the hour circle of a celestial body.
- simple carbohydrate — a carbohydrate, as glucose, that consists of a single monosaccharide unit.
- simple closed curve — a curve that is closed and that has no loops or points missing; a curve for which there exists a homeomorphism mapping it to a circle.
- slate-colored junco — the eastern subspecies of the dark-eyed junco, Junco hyemalis, having grayer plumage than the several western subspecies.
- smokestack industry — A smokestack industry is a traditional industry such as heavy engineering or manufacturing, rather than a modern industry such as electronics.
- sodium hydrosulfite — a white, crystalline, water-soluble powder, Na 2 S 2 O 4 , used as a reducing agent, especially in dyeing, and as a bleach.
- sodium hypochlorite — a pale-green, crystalline compound, NaOCl, unstable in air, soluble in cold water, decomposes in hot water: used as a bleaching agent for paper and textiles, in water purification, in household use, and as a fungicide.
- soft-shelled turtle — any of numerous aquatic turtles of the family Trionychidae, inhabiting North America, Asia, and Africa, having the shell covered with flexible, leathery skin instead of horny plates.
- solid of revolution — a three-dimensional figure formed by revolving a plane area about a given axis.
- south african dutch — the Boers.
- spotted wintergreen — an evergreen plant, Chimaphila maculata, of central North America, having leaves with mottled-white veins and white, fragrant flowers.
- spread oneself thin — to draw, stretch, or open out, especially over a flat surface, as something rolled or folded (often followed by out).
- staff-student ratio — the ratio of teachers to pupils or students in a school, college, or university
- stakeholder pension — In Britain, a stakeholder pension is a flexible pension scheme with low charges. Both employees and the state contribute to the scheme, which is optional, and is in addition to the basic state pension.