stamina

noun

1. (uncountable, usually)The energy and strength for continuing to do something over a long period of time; power of sustained exertion, or resistance to hardship, illness etc.

   “He has a lot of stamina. I suppose that's why he can run for a long time.”

   “In the first five minutes muscles which he had not been aware that he possessed had started to ache like neglected teeth. His respect for the toughness and durability of artists' models was now solid. How they acquired the stamina to go through this sort of thing all day and then bound off to Bohemian revels at night was more than he could understand.”

2. (obsolete, plural, plural-only, uncountable, usually)The basic elements of a thing; rudimentary structures or qualities.
3. (form-of, plural, rare)plural of stamen

   “1790, William Curtis, The Botanical Magazine, Or, Flower-Garden Displayed, Volume 3, 2006 Gutenberg eBook edition, In the specimens we have examined, and which perhaps have been rendered luxuriant by culture, the number of stamina has been from twelve to sixteen; of styles, from six to eight; of flowers on the same stalk, from one to eight.”