(mathematics) A polynomial equation whose greatest exponent is 3.

(military) A line drawn on a map or chart connecting all points at which the magnetic inclination (dip) is zero for a specified epoch.

(number theory) A polynomial equation whose variables are only permitted to assume integer values.

plural of Diophantine equation

(astronomy) A great circle on the celestial sphere, coincident with the plane of earth's equator.

plural of celestial equator

(physics) A relativistic wave equation that describes an electron (and similar particles); it predicted the existence of antiparticles

plural of differential equation

(chemistry) Either of two equations that describe each half of a redox reaction

(mathematics) An equation defining a curve in terms of radius and angle.