in·cli·na·tion / ˌinkləˈnāshən; ˌingklə-/ • n. 1. a person's natural tendency or urge to act or feel in a particular way; a disposition or propensity: John was a scientist by training and inclination | he was free to follow his inclinations. ∎  (inclination for/to/toward) an interest in or liking for (something): Burger King and Wendy's didn't show any inclination to jump into a price war with McDonald's.2. a slope or slant: changes in inclination of the line on the graph. ∎  a bending of the body or head in a bow: the questioner's inclination of his head. ∎  the dip of a magnetic needle.3. the angle at which a straight line or plane is inclined to another. ∎  Astron. the angle between the orbital plane of a planet, comet, etc., and the ecliptic, or between the orbital plane of a satellite and the equatorial plane of its primary. ∎ Astron. the angle between the axis of an astronomical object and a fixed reference angle.

inclination The angle between the horizontal and a magnetic vector. Conventionally, a vector with a magnetic north pole dipping below the horizontal is considered positive, and an upward vector is negative.