Breadcrumb Home > Dictionary > Index I inclined plane: Meaning and Definition of Find definitions for: inclined' plane' Pronunciation: [key] one of the simple machines, a plane surface inclined to the horizon, or forming with a horizontal plane any angle but a right angle. Cf. machine (def. 4b). incline (def. 11a). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. inclined inclining ✖ Related Content Daily Word Quiz: unctuous Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language