law, law of nature

a generalization that describes recurring facts or events in nature; "the laws of thermodynamics"

• all-or-none law — (neurophysiology) a nerve impulse resulting from a weak stimulus is just as strong as a nerve impulse resulting from a strong stimulus
• principle, rule — a rule or law concerning a natural phenomenon or the function of a complex system
• Archimedes' principle, law of Archimedes — (hydrostatics) the apparent loss in weight of a body immersed in a fluid is equal to the weight of the displaced fluid
• Avogadro's law, Avogadro's hypothesis — the principle that equal volumes of all gases (given the same temperature and pressure) contain equal numbers of molecules
• Bernoulli's law, law of large numbers — (statistics) law stating that a large number of items taken at random from a population will (on the average) have the population statistics
• Bose-Einstein statistics — (physics) statistical law obeyed by a system of particles whose wave function is not changed when two particles are interchanged (the Pauli exclusion principle does not apply)
• Boyle's law, Mariotte's law — the pressure of an ideal gas at constant temperature varies inversely with the volume
• Coulomb's Law — a fundamental principle of electrostatics; the force of attraction or repulsion between two charged particles is directly proportional to the product of the charges and inversely proportional to the distance between them; principle also holds for magnetic poles
• Dalton's law, Dalton's law of partial pressures, law of partial pressures — (chemistry and physics) law stating that the pressure exerted by a mixture of gases equals the sum of the partial pressures of the gases in the mixture; the pressure of a gas in a mixture equals the pressure it would exert if it occupied the same volume alone at the same temperature
• distribution law — (chemistry) the total energy in an assembly of molecules is not distributed equally but is distributed around an average value according to a statistical distribution
• equilibrium law, law of chemical equilibrium — (chemistry) the principle that (at chemical equilibrium) in a reversible reaction the ratio of the rate of the forward reaction to the rate of the reverse reaction is a constant for that reaction
• Fechner's law, Weber-Fechner law — (psychophysics) the concept that the magnitude of a subjective sensation increases proportional to the logarithm of the stimulus intensity; based on early work by E. H. Weber
• Fermi-Dirac statistics — (physics) law obeyed by a systems of particles whose wave function changes when two particles are interchanged (the Pauli exclusion principle applies)
• Gay-Lussac's law, Charles's law, law of volumes — (physics) the density of an ideal gas at constant pressure varies inversely with the temperature
• Henry's law — (chemistry) law formulated by the English chemist William Henry; the amount of a gas that will be absorbed by water increases as the gas pressure increases
• Hooke's law — (physics) the principle that (within the elastic limit) the stress applied to a solid is proportional to the strain produced
• Hubble's law, Hubble law — (astronomy) the generalization that the speed of recession of distant galaxies (the red shift) is proportional to their distance from the observer
• Kepler's law, Kepler's law of planetary motion — (astronomy) one of three empirical laws of planetary motion stated by Johannes Kepler
• Kirchhoff's laws — (physics) two laws governing electric networks in which steady currents flow: (1) the sum of all the currents at a point is zero; (2) the sum of the voltage gains and drops around any closed circuit is zero
• law of averages — a law affirming that in the long run probabilities will determine performance
• law of constant proportion, law of definite proportions — (chemistry) law stating that every pure substance always contains the same elements combined in the same proportions by weight
• law of diminishing returns — a law affirming that to continue after a certain level of performance has been reached will result in a decline in effectiveness
• law of effect — (psychology) the principle that behaviors are selected by their consequences; behavior having good consequences tends to be repeated whereas behavior that leads to bad consequences is not repeated
• law of equivalent proportions, law of reciprocal proportions — (chemistry) law stating that the proportions in which two elements separately combine with a third element are also the proportions in which they combine together
• law of gravitation, Newton's law of gravitation — (physics) the law that states any two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them
• law of multiple proportions, Dalton's law — (chemistry) law stating that when two elements can combine to form more than one compound the amounts of one of them that combines with a fixed amount of the other will exhibit a simple multiple relation
• law of mass action — (chemistry) the law that states the following principle: the rate of a chemical reaction is directly proportional to the molecular concentrations of the reacting substances
• law of thermodynamics — (physics) a law governing the relations between states of energy in a closed system
• Mendel's law — (genetics) one of two principles of heredity formulated by Gregor Mendel on the basis of his experiments with plants; the principles were limited and modified by subsequent genetic research
• Newton's law of motion, Newton's law, law of motion — one of three basic laws of classical mechanics
• Ohm's law — electric current is directly proportional to voltage and inversely proportional to resistance; I = E/R
• Pascal's law, Pascal's law of fluid pressures — pressure applied anywhere to a body of fluid causes a force to be transmitted equally in all directions; the force acts at right angles to any surface in contact with the fluid
• Pauli exclusion principle, exclusion principle — no two electrons or protons or neutrons in a given system can be in states characterized by the same set of quantum numbers
• periodic law, Mendeleev's law — (chemistry) the principle that chemical properties of the elements are periodic functions of their atomic numbers
• Planck's law — (physics) the basis of quantum theory; the energy of electromagnetic waves is contained in indivisible quanta that have to be radiated or absorbed as a whole; the magnitude is proportional to frequency where the constant of proportionality is give by Planck's constant
• Planck's radiation law — (physics) an equation that expresses the distribution of energy in the radiated spectrum of an ideal black body
• principle of relativity — (physics) a universal law that states that the laws of mechanics are not affected by a uniform rectilinear motion of the system of coordinates to which they are referred
• Weber's law — (psychophysics) the concept that a just-noticeable difference in a stimulus is proportional to the magnitude of the original stimulus

• concept, conception, construct — an abstract or general idea inferred or derived from specific instances

• theory — 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