[From Latin transcendentalis: going beyond or above something.]
(metaphysics) Any approach to philosophy holding that there is an aspect of reality higher than the physical world of perception and experience; another term for idealism, often used to refer to Kantianism or even spiritualism.
(ethics) A school of 19th century American philosophy exemplified by Ralph Waldo Emerson (1803-1882) and Henry David Thoreau (1817-1862); it advocated a combination of optimism and individualism that emphasized self-reliance and self-fulfillment in harmony with nature and humanistic ideals.