The Question:

What is a "pyrrhic victory," and why is it called that?

The Answer:

A pyrrhic victory is a victory won at too great a cost. The name comes from Pyrrhus (319 B.C.-272 B.C.), king of Epirus. After defeating the Romans in 279 B.C. while sustaining very heavy losses, Pyrrhus declared "one more such victory and I am lost."

—The Fact Monster