1. The fixed, firm part of a body, which supports it or gives it strength and solidity; as, the bones are the stamina of animal bodies; the ligneous parts of trees are the stamina which constitute their strength.
2. Whatever constitutes the principal strength or support of anything; power of endurance; backbone; vigor; as, the stamina of a constitution or of life; the stamina of a state. He succeeded to great captains who had sapped the whole stamina and resistance of the contest. (De Quincey)