imagination

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The ability to form mental images of things that are not present to the senses or not considered to be real.
• noun The formation of such images.
• noun One of these mental images.
• noun The mind viewed as the locus or repository of this ability or these images.
• noun The ability to confront and deal with reality by using the creative power of the mind; resourcefulness.
• noun Attention, interest, or enthusiasm.

from The Century Dictionary.

• noun In entomology, the act of transforming into an imago or of reaching the imaginal stage: said of insects completing their metamorphosis.
• noun The act or faculty of forming a mental image of an object; the act or power of presenting to consciousness objects other than those directly and at that time produced by the action of the senses; the act or power of reproducing or recombining remembered images of sense-objects; especially, the higher form of this power exercised in poetry and art.
• noun An image in the mind; a formulated conception or idea.
• noun The act of devising, planning, or scheming; a contrivance; scheme; device; plot.
• noun A baseless or fanciful opinion.
• noun Synonyms Imagination, Fancy. By derivation and early use fancy has the same meaning as imagination, but the words have become more and more distinctly separated. (See Wordsworth's preface to his “Lyrical Ballads.”) Imagination is the more profound, earnest, logical. Fancy is lighter, more sportive, and often more purely creative. We call “Hamlet” and “Macbeth” works of Shakspere's imagination, the “Midsummer Night's Dream” and “The Tempest” of his fancy.

from the GNU version of the Collaborative International Dictionary of English.

• noun The imagine-making power of the mind; the power to create or reproduce ideally an object of sense previously perceived; the power to call up mental imagines.
• noun The representative power; the power to reconstruct or recombine the materials furnished by direct apprehension; the complex faculty usually termed the plastic or creative power; the fancy.
• noun The power to recombine the materials furnished by experience or memory, for the accomplishment of an elevated purpose; the power of conceiving and expressing the ideal.
• noun A mental image formed by the action of the imagination as a faculty; a conception; a notion.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The image-making power of the mind; the act of creating or reproducing ideally an object not previously perceived; the ability to create such images.
• noun Particularly, construction of false images; fantasizing.
• noun Creativity; resourcefulness.
• noun A mental image formed by the action of the imagination as a faculty; a conception; a notion; an imagining; something imagined.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the formation of a mental image of something that is not perceived as real and is not present to the senses
• noun the ability to form mental images of things or events
• noun the ability to deal resourcefully with unusual problems