"The formation of a mental image of something that is neither perceived as real nor present to the senses."[1] "imagination," The American Heritage Dictionary of the English Language, 4th ed.
In my usage, such an "image" need not be visual. As examples, it's possible to imagine the sound of a bird, the taste of a strawberry, or the aroma of a flower. A person can mentally project images, sounds, flavors, aromas, sense-perceptions, and countless details — even if, at the moment, that person doesn't perceive one or more of these by means of sense-perception.
I can't see my daughter at the moment, yet I can imagine her vividly. I can even imagine her doing things, such as piloting an airplane, that I've never yet seen her do. I draw upon my memories of airplanes and of Aliana's motions, bring these memories together, and with my imagination project something that I've not yet experienced. So my image of Aliana piloting an airplane exists — but purely in an imaginary manner.
