The Collaborative International Dictionary of English v.0.48:
Virtue \Vir"tue\ (?; 135), n. [OE. vertu, F. vertu, L. virtus
strength, courage, excellence, virtue, fr. vir a man. See
Virile, and cf. Virtu.]
1. Manly strength or courage; bravery; daring; spirit; valor.
Built too strong
For force or virtue ever to expugn. --Chapman.
2. Active quality or power; capacity or power adequate to the
production of a given effect; energy; strength; potency;
efficacy; as, the virtue of a medicine.
Jesus, immediately knowing in himself that virtue
had gone out of him, turned him about. --Mark v. 30.
A man was driven to depend for his security against
misunderstanding, upon the pure virtue of his
syntax. --De Quincey.
The virtue of his midnight agony. --Keble.
3. Energy or influence operating without contact of the
material or sensible substance.
She moves the body which she doth possess,
Yet no part toucheth, but by virtue's touch. --Sir.
4. Excellence; value; merit; meritoriousness; worth.
I made virtue of necessity. --Chaucer.
In the Greek poets, . . . the economy of poems is
better observed than in Terence, who thought the
sole grace and virtue of their fable the sticking in
of sentences. --B. Jonson.
5. Specifically, moral excellence; integrity of character;
purity of soul; performance of duty.
Virtue only makes our bliss below. --Pope.
If there's Power above us,
And that there is all nature cries aloud
Through all her works, he must delight in virtue.
6. A particular moral excellence; as, the virtue of
temperance, of charity, etc. "The very virtue of
compassion." --Shak. "Remember all his virtues."
7. Specifically: Chastity; purity; especially, the chastity
of women; virginity.
H. I believe the girl has virtue.
M. And if she has, I should be the last man in the
world to attempt to corrupt it. --Goldsmith.
8. pl. One of the orders of the celestial hierarchy.
Thrones, dominations, princedoms, virtues, powers.
Cardinal virtues. See under Cardinal, a.
In virtue of, or By virtue of, through the force of; by
authority of. "He used to travel through Greece by virtue
of this fable, which procured him reception in all the
towns." --Addison. "This they shall attain, partly in
virtue of the promise made by God, and partly in virtue of
Theological virtues, the three virtues, faith, hope, and
charity. See --1 Cor. xiii. 13.