Since the Young Women added virtue to their list of values, I've heard several talks on its importance. While preparing to give one myself, (our Relief Society Birthday Enrichment theme was from D&C 25:2 - "walk in the path of virtue") I found the following note in my scriptures:
Virtue: the strength to do well and consistently the tedious tasks of daily life.
That sent me looking for the original quote - which was given in a BYU devotional talk on 18 September 2007 by President Gordon B. Hinckley. His topic was the 13th Article of Faith. Since I had the privilege of attending in person, (it was the day before I took Brad to the MTC), that's the note that I wrote to myself because I loved the idea. Here's what President Hinckley really said:
"We believe in being virtuous. This may have nothing whatever to do with sexual morality; that is covered by the word chaste. Virtuous, in this case, I believe, means having strength—the strength to do whatever needs doing. Great virtue comes in doing well and consistently the everyday, often rather tedious tasks of life. Blaise Pascal said that 'the strength of a man’s virtue should not be measured by his special exertions, but by his habitual acts' (Pensées ).
"Your virtue will be attained through deliberate practice of those things that bring strength and purity to your life—such things as prayer; consistent study of the scriptures; timely payment of your financial obligations, especially an honest tithe; careful adherence to the law of health, which we call the Word of Wisdom; and faithful observance of all the commandments of God. These and other goodly practices performed on a habitual basis will yield great virtue."
The other definition I like comes from Preach My Gospel, through Sister Elaine Dalton's October 2008 general conference talk:
"Virtue is a pattern of thought and behavior based on high moral standards; the accumulation of thousands of small decisions and actions. Virtuous women possess a quiet dignity and inner strength. They are confident because they are worthy to receive and be guided by the Holy Ghost."
What a great quality to try and develop!