(chemistry) An equation which approximates the dependence of the rate of any chemical reaction on the temperature.

(calculus) an equation involving the derivatives of a function

(mathematics) a polynomial equation of the second degree.

(mathematics) A polynomial equation of the first degree (such as x = 2y - 7)

(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.

(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