n. A bending or sloping downward; a sloping or bending from a higher to a lower level; subsidence: as, the declination of the shore.n. A falling to a lower or inferior condition; deterioration; decline: as, declination in or of vigor, virtue, morals, etc.n. Deviation from a right line; oblique motion.n. Deviation from the right path or course of conduct: as, a declination from duty.n. Aversion; disinclination.n. The act of declining, refusing, or shunning; refusal: as, a declination of an office.n. In astronomy, the distance of a heavenly body from the celestial equator, measured on a great circle passing through the pole and also through the body.n. The angle between the magnetic meridian and the geographical meridian of a place.n. In dialing, the arc of the horizon contained between the vertical plane and the prime vertical circle, if reckoned from east or west, or between the meridian and the plane, if reckoned from north or south.n. In grammar, declension; the inflection of a noun through its various terminations.