18-letter words starting with ra
- rabbit's-foot fern — hare's-foot fern.
- rabbit-foot clover — a plant, Trifolium arvense, having trifoliate leaves with narrow leaflets and fuzzy, cylindrical, grayish-pink flower heads.
- rabbit-proof fence — a fence through which rabbits are unable to pass
- racial segregation — social policy: separation of races
- racially motivated — motivated by (the hate or prejudice of) someone's race
- radiant efficiency — the ratio of the power emitted by a source of radiation to the power consumed by it
- radiation exposure — exposure to radiant energy or to the particles emitted in the transfer of radiant energy, esp the particles and gamma rays emitted in nuclear decay; exposure to radioactive substances
- radiation pressure — the pressure exerted on a surface by electromagnetic radiation or by sound waves.
- radiation sickness — sickness caused by irradiation with x-rays or other nuclear radiation as a result of therapeutic treatment, accidental exposure, or a nuclear bomb explosion and characterized by nausea, vomiting, headache, cramps, diarrhea, loss of hair and teeth, destruction of white blood cells, and prolonged hemorrhage.
- radical empiricism — (in the philosophy of William James) the doctrine that the only proper subject matter of philosophy is that which can be defined in terms of experience, and that relations are a part of experience.
- radical expression — an expression in which radical signs appear.
- radio range beacon — a radio transmitter that utilizes two or more directional antennas and transmits signals differing with direction, permitting a flier receiving a signal to determine his or her approximate bearing from the transmitter without a radio compass.
- radioactive dating — any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product.
- radioactive series — a succession of elements initiated in the radioactive decay of a parent, as thorium or uranium, each of which decays into the next until a stable element, usually lead, is produced.
- radiocarbon dating — the determination of the age of objects of organic origin by measurement of the radioactivity of their carbon content.
- radiocommunication — communication by means of radio waves
- radiometric dating — any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product.
- radius of gyration — the distance from an axis at which the mass of a body may be assumed to be concentrated and at which the moment of inertia will be equal to the moment of inertia of the actual mass about the axis, equal to the square root of the quotient of the moment of inertia and the mass.
- raffinate recovery — Raffinate recovery is the use of a substance which is left after a process is complete and the desired substances have been removed.
- ragtag and bobtail — the riffraff; rabble: The ragtag and bobtail of every nation poured into the frontier in search of gold.
- rail rapid transit — a system of rail transit within an urban area that has exclusive right of way either below, above, or on the ground and so is capable of relatively high operating speed. Abbreviation: RRT.
- rain cats and dogs — water that is condensed from the aqueous vapor in the atmosphere and falls to earth in drops more than 1/50 inch (0.5 mm) in diameter. Compare drizzle (def 6).
- raman spectroscopy — a form of spectroscopy which uses the Raman effect for studying molecules
- random walk theory — the theory that the future movement of share prices does not reflect past movements and therefore will not follow a discernible pattern
- range of stability — the angle to the perpendicular through which a vessel may be heeled without losing the ability to right itself.
- rape crisis centre — a place that provides support to people who have been victims of rape or other kinds of sexual abuse
- rapid eye movement — rapidly shifting, continuous movements of the eyes beneath closed lids during the stage of sleep characterized by dreaming.
- rare-earth element — any of a group of closely related metallic elements, comprising the lanthanides, scandium, and yttrium, that are chemically similar by virtue of having the same number of valence electrons.
- rational operation — any of the mathematical operations of addition, subtraction, multiplication, and division.
- rattlesnake master — any of various plants of the genus Eryngium, especially E. yuccifolium, having spiny leaves and dense, rounded flower heads.
On this page, we collect all 18-letter words starting with RA. It’s easy to find right word with a certain length. It is the easiest way to find 18-letter word that beginning with RA to use in Scrabble or Crossword puzzles.