a belief that can guide behavior; "the architect has a theory that more is less"; "they killed him on the theory that dead men tell no tales"
a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory"
the discipline that studies the principles of transmiting information and the methods by which it is delivered (as print or radio or television etc.); "communications is his major field of study"
a set of techniques for exploring underlying motives and a method of treating various mental disorders; based on the theories of Sigmund Freud; "his physician recommended psychoanalysis"
(biology) the field of science concerned with processes of communication and control (especially the comparison of these processes in biological and artificial systems)
the branch of quantum physics that accounts for matter at the atomic level; an extension of statistical mechanics based on quantum theory (especially the Pauli exclusion principle)
(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"
(psychology) a theory that reduces all mental phenomena to simple elements (sensations and feelings) that form complex ideas by association
under or below an object or a surface; at a lower place or level; directly beneath; "we could see the original painting underneath"; "a house with a good foundation underneath"
on the lower or downward side; on the underside of; "a chest of drawers all scratched underneath"
a turn toward the side of the body that is on the north when the person is facing east; "take a left at the corner"
the hand that is on the left side of the body; "jab with your left"
those who support varying degrees of social or political or economic change designed to promote the public welfare
location near or direction toward the left side; i.e. the side to the north when a person or object faces east; "she stood on the left"
of or belonging to the political or intellectual left
being or located on or directed toward the side of the body to the west when facing north; "my left hand"; "left center field"; "the left bank of a river is bank on your left side when you are facing downstream"
toward or on the left; also used figuratively; "he looked right and left"; "the political party has moved left"