A theory or conception of something in its absolute perfection. Or, a standard or model of excellence. Also, an ultimate object of endeavor; a goal. And, an honorable or worthy principle or aim.Example: Leonardo da Vinci (Italian, 1452-1519), Study of proportions, from Vitruvius's De Architectura, pen and ink, 13 1/2 x 9 5/8 inches (34.3 x 24.5 cm), Accademia, Venice. Leonardo, inspired by the mathematician Vitruvius (Roman, 1st century BCE), drew this famous picture of Vitruvian Man ? a sort of ideal figure ? whose arm span is equal to his height ? a ratio of one, or 1:1. See a page with a math lesson plan for grades 6-8, as well as articles on drawing, proportion, and Renaissance.Also see archetype, avatar, exemplar, icon, idealism, idealization, and standards.