Imagination is derived from the Latin word, imagination, which means "image". This is also equivalent to the Latin word, phantasia, which itself derives from the Greek word, phantos, meaning "visible". It first came into use by Aristotle in philosophy when he stated, “the soul never thinks without a mental image [phantasa]”.This term is used to describe the product or process of the mind’s ability to form and manipulate images, concepts, mental pictures, or hallucinations. These mental images are new sensations unable to be perceived through sight, hearing or any other senses. 
Imagination has many key functions, firstly, imagination can form alternative possibilities for situations and problems. Imagination is limitless in resources and is therefore a method to problem solving due to its ability to form multiple resolutions. Secondly, imagination plays a crucial role in the learning process because it is able to provide meaning to experiences and understanding to knowledge. For instance, imagination aids in analyzing because due to an imaginative input, one is able to approach the next logical step.  In addition, imagination can also be a form of healing. For instance, one can use their imagination to influence their temperament, the most known and popular term is to “imagine your happy place”. Imagination is also a form of storytelling, like fairy-tales or fantasy. A common example of exercised imagination would be children playing pretend through use of narratives in the form of role-playing.
To this day, imagination remains one of the top tools of the trade. Without imagination, one is forever limited to what he or she sees, feels, hears, and knows. To imagine is to question the realm of reality and to create what is not there, as a result, it expands reality for everyone, and like a cycle, influences those who sees the idea to create their own. Imagination is an invaluable tool compared to the limitations of artificial intelligence and its incapability to create unforeseen concepts. For this reason, imagination is significantly important in the practice of architecture. When an architect encounters a design problem, he or she must approach the problem with tools at hand and instinctively, imagination is used as a default processor to motivate the brain to stimulate different ideas. From imagination, one is able to create things that were never present before. From sky scrapers to ancient tombs, all the structures that were nonexistent suddenly exist. All that can be imagined may eventually become reality and concepts once regarded as impossible are now available and would never have become true if not for the individual with the idea - the imagination.
 Harper, Douglas. Online Etymology, "Imagination." Accessed November 13, 2012. http://www.etymonline.com/index.php?term=imagination.
 Thomas, Nigel J.T. Philosophy of Mind, "Imagination." Last modified 2004. Accessed November 13, 2012. http://philosophy.uwaterloo.ca/MindDict/imagination.html
 McLean, George F. "The Role of Imagination." Accessed November 13, 2012. http://www.crvp.org/seminar/05-seminar/mclean.htm.
 Oxford English Dictionary, "imagination, n.." Last modified 2009. Accessed November 13, 2012. http://www.oed.com.proxy.lib.uwaterloo.ca/view/Entry/91643?redirectedFrom=imagination
 Kime, A.O. Matrix of Mnemosyne, "The Human Imagination... the nemesis of cognitive science." Last modified 2008. Accessed November 13, 2012. http://www.matrixbookstore.biz/imagination.htm.