The Collaborative International Dictionary
Theory \The"o*ry\, n.; pl. Theories. [F. th['e]orie, L. theoria, Gr. ? a beholding, spectacle, contemplation, speculation, fr. ? a spectator, ? to see, view. See Theater.]
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A doctrine, or scheme of things, which terminates in speculation or contemplation, without a view to practice; hypothesis; speculation.
Note: ``This word is employed by English writers in a very loose and improper sense. It is with them usually convertible into hypothesis, and hypothesis is commonly used as another term for conjecture. The terms theory and theoretical are properly used in opposition to the terms practice and practical. In this sense, they were exclusively employed by the ancients; and in this sense, they are almost exclusively employed by the Continental philosophers.''
--Sir W. Hamilton. An exposition of the general or abstract principles of any science; as, the theory of music.
The science, as distinguished from the art; as, the theory and practice of medicine.
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The philosophical explanation of phenomena, either physical or moral; as, Lavoisier's theory of combustion; Adam Smith's theory of moral sentiments.
Atomic theory, Binary theory, etc. See under Atomic, Binary, etc.
Syn: Hypothesis, speculation.
Usage: Theory, Hypothesis. A theory is a scheme of the relations subsisting between the parts of a systematic whole; an hypothesis is a tentative conjecture respecting a cause of phenomena.
Atomic \A*tom"ic\, Atomical \A*tom"ic*al\, a. [Cf. F. atomique.]
Of or pertaining to atoms.
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Extremely minute; tiny.
Atomic bomb, see atom bomb in the vocabulary.
Atomic philosophy, or Doctrine of atoms, a system which, assuming that atoms are endued with gravity and motion, accounted thus for the origin and formation of all things. This philosophy was first broached by Leucippus, was developed by Democritus, and afterward improved by Epicurus, and hence is sometimes denominated the Epicurean philosophy.
Atomic theory, or the Doctrine of definite proportions (Chem.), teaches that chemical combinations take place between the supposed ultimate particles or atoms of bodies, in some simple ratio, as of one to one, two to three, or some other, always expressible in whole numbers.
Atomic weight (Chem.), the weight of the atom of an element as compared with the weight of the atom of hydrogen, taken as a standard.
Wiktionary
n. 1 (context physics English) The theory that all gross matter is composed of atoms. 2 (context physics English) Any of several theories that explain the structure of the atom, and of subatomic particles.
WordNet
n. a theory of the structure of the atom
(chemistry) any theory in which all matter is composed of tiny discrete finite indivisible indestructible particles; "the ancient Greek philosophers Democritus and Epicurus held atomic theories of the universe" [syn: atomism, atomist theory, atomistic theory] [ant: holism]
Wikipedia
In chemistry and physics, atomic theory is a scientific theory of the nature of matter, which states that matter is composed of discrete units called atoms. It began as a philosophical concept in ancient Greece and entered the scientific mainstream in the early 19th century when discoveries in the field of chemistry showed that matter did indeed behave as if it were made up of atoms.
The word atom comes from the Ancient Greek adjective atomos, meaning "uncuttable". 19th century chemists began using the term in connection with the growing number of irreducible chemical elements. While seemingly apropos, around the turn of the 20th century, through various experiments with electromagnetism and radioactivity, physicists discovered that the so-called "uncuttable atom" was actually a conglomerate of various subatomic particles (chiefly, electrons, protons and neutrons) which can exist separately from each other. In fact, in certain extreme environments, such as neutron stars, extreme temperature and pressure prevents atoms from existing at all. Since atoms were found to be divisible, physicists later invented the term " elementary particles" to describe the "uncuttable", though not indestructible, parts of an atom. The field of science which studies subatomic particles is particle physics, and it is in this field that physicists hope to discover the true fundamental nature of matter.
Usage examples of "atomic theory".
Trained by Dalton, the founder of the atomic theory, in experimental research, he continued Rumford's and Davy's researches which they had undertaken to prove that heat is not, as it was for a time believed to be, a ponderable substance, but an imponderable agent.
It was in 1913 that the Danish Nobel Prize winner Niels Bohr (1885-1962) laid the foundations of atomic theory with his atomic model.
There were Greek philosophers once, named Leucippus and Democritus, who evolved an atomic theory.
Jew, had held a top post in Moscow's Kurehatov Institute of Atomic Energy, where he was viewed by his fellow theo-rists with equal amounts of awe and suspicion, mainly because he was a genius not only in atomic theory but in theoretical-language design.
They gazed with some indignation at the retreating back of Professor Fitzsimmons as, wearing his oldest hiking outfit and engrossed in a difficult piece of atomic theory, he dwindled down the lane.
He evolved an atomic theory: All matter was composed of tiny particles, too small to be seen.
Rather ignorant, I'm afraid, of life and politics and warof nearly everything, I suppose, except atomic theory.
Conceptually, the universe had been a reasonably comfortable place to live in, in primitive atomic theory which offered the assurance that everything, earth, air, fire or water, steel and oranges, man or star, was ultimately composed of submicroscopic vortices called protons and electrons leavened a little with neutrons and neutrinos which had no charge, and bound together by a disorderly but homely family of mesons.
The first concerns the Danish Nobel Prize winner Niels Bohr (1885-1962), who laid the foundations for present-day atomic theory.