"stamina": 1. 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." Source and further information: http://en.wiktionary.org/wiki/stamina "endurance": 1. The measure of a person's stamina or persistence. He has great endurance, he ran a marathon and then rode his bicycle home. 2. Ability to endure hardship." Source and further information: http://en.wiktionary.org/wiki/endurance

In everyday speech, I would argue that stamina and endurance are the same thing and that these two words can be used interchangeably. However, if you must know the (extremely subtle) difference, please look at my explanation below :) Stamina is "the ability to sustain prolonged physical or mental effort" where to sustain means "to strengthen or support physically or mentally." To sustain also has a nuance of continuity. In other words, stamina is the ability to support continually prolonged effort, physically or mentally. Endurance is "the fact or power of enduring an unpleasant or difficult process or situation without giving way" where to endure means "to suffer patiently." In other words, endurance is the ability to suffer unpleasant or difficult situations without giving way. The only difference that I can see is that the definition for stamina does not require the activity to be unpleasant/difficult, it just has to last a prolonged period of time; whereas in endurance, there is a requirement for the activity to be unpleasant/difficult. Other than this, they're the same thing. (Definitions from Google)