Moral excellence and righteousness; goodness. An example or kind of moral excellence: the virtue of patience. Chastity, especially in a woman. A particularly efficacious, good, or beneficial quality; advantage: a plan with the virtue of being practical. Effective force or power: believed in the virtue of prayer. Christianity The fifth of the nine orders of angels in medieval angelology. Obsolete Manly courage; valor. by On the grounds or basis of; by reason of: well-off by virtue of a large inheritance.