Mathematics and Physics Glossary

Galactic circle (Astron.), the great circle of the heavens, to which the course of the galaxy most nearly conforms. Herschel.

Galaxy n.; pl. Galaxies. (Astron.) The Milky Way; that luminous tract, or belt, which is seen at night stretching across the heavens, and which is composed of innumerable stars, so distant and blended as to be distinguishable only with the telescope. The term has recently been used for remote clusters of stars.

Galois theory, n. (Math.) An area of group theory concerned with the conditions under which a polynomial equation of power n with coefficients in a given mathematical field can be solved by repeating given operations and extracting the nth roots.

Galvanism n. (Phys.) (a) Electricity excited by the mutual action of certain liquids and metals; dynamical electricity. (b) The branch of physical science which treats of dynamical elecricity, or the properties and effects of electrical currents.

Game, n. (Math.) A model of a competitive situation used in game theory to determine the optimal course of action.

Game theory, n. A mathematical method of decision-making in which a competitive situation is analyzed to determine the optimal course of action, often used in political, economic, and military planning.