Pronunciation: (dou, tou), [key]
—n. (sometimes l.c.)
1. (in philosophical Taoism) that in virtue of which all things happen or exist.
2. the rational basis of human activity or conduct.
3. a universal, regarded as an ideal attained to a greater or lesser degree by those embodying it.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.