Greek, 18th century
A thing as it is in itself, as distinct from a thing as it is knowable by the senses through phenomenal attributes (in Kantian philosophy). “Noumenon” is based on the Greek “νοούμενον,” meaning “something that is conceived with the mind.” This was in direct contrast to “phenomenon,” which came from the Greek “φαινόμενον,” meaning “that which appears visibly.”
German philosopher Immanuel Kant coined the word “noumenon” (and the plural “noumena”) in 1783 in an effort to describe things occurring outside of appearances visible to human beings. “Noumenon” describes a transcendental thing too great to be fully conceived with limited human capacities. Kant used the word in direct contrast to “phenomenon,” which is a fact or event perceptible to humans through their senses.
Example: My unique views on life manifest themselves as the noumenon of my stories.