endurance

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act, quality, or power of withstanding hardship or stress.
• noun The state or fact of persevering.
• noun Continuing existence; duration.

from The Century Dictionary.

• noun Continuance; duration.
• noun Continuance in bearing or suffering; the fact or state of enduring stress, hardship, pain, or the like; a holding out under adverse force or influence of any kind: as, the endurance of iron or timber under great strain; a person's endurance of severe affliction.
• noun Ability to endure; power of bearing or suffering without giving way; capacity for continuance under stress, hardship, or infliction; as, to test the endurance of a brand of steel; that is beyond endurance, or surpasses endurance.
• noun Delay; procrastination.
• noun [The meaning of the word in the above extract has been disputed, some thinking it equivalent to durance, confinement; others, to suffering.] Synonyms and Fortitude, etc. (see patience); permanence, persistence, continuance, suffering, sufferance, tolerance.

from the GNU version of the Collaborative International Dictionary of English.

• noun A state or quality of lasting or duration; lastingness; continuance.
• noun The act of bearing or suffering; a continuing under pain or distress without resistance, or without being overcome; sufferance; patience.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The measure of a person's stamina or persistence.
• noun Ability to endure hardship.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a state of surviving; remaining alive
• noun the power to withstand hardship or stress