Final answer:
Illumination, based on the root 'lucere', refers to the action of lighting up or the effect of being lit up, and can also indicate enlightening someone intellectually or spiritually, often associated with divine light as seen in Gothic architecture.
Step-by-step explanation:
The root lucere means to make bright or light up. The best definition of illumination, when considering this root, would be the action of supplying or brightening with light or the effect of being lit up. In broader terms, illumination can also refer to the process of enlightening or providing intellectual or spiritual light. This concept of illumination was embodied in the architectural designs of Abbot Suger, who cherished the idea of lux nova, or 'new light', which he associated with the divine aura created by colorful stained glass windows in Gothic cathedrals that allowed light to dramatically transform the interior spaces. The purpose of illumination in this context was not only to physically brighten, but also to uplift the soul and mind to a sense of the divine. Moreover, in visual arts, as with the artist's intention mentioned in the question, illumination can denote a sense of clarity and depth of understanding conveyed through the artwork.