From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( n.) The system or theory that denies the existence of material bodies, and teaches that we have no rational grounds to believe in the reality of anything but ideas and their relations.

(2): ( n.) Conception of the ideal; imagery.

(3): ( n.) The quality or state of being ideal.

(4): ( n.) The practice or habit of giving or attributing ideal form or character to things; treatment of things in art or literature according to ideal standards or patterns; - opposed to realism.

The Nuttall Encyclopedia [2]

That view of the universe which, in opposition to Materialism ( q. v .), refers everything to and derives everything from a spiritual root; is Subjective if traced no further back than the ego , and Objective if traced back to the non-ego likewise, its counterpart, or other, in the objective world. Idealism in art is art more or less at work in the region of the ideal in comparative disregard of the actual.