The Collaborative International Dictionary of English v.0.48:

Stamina \Stam"i*na\ (st[a^]m"[i^]*n[.a]), n. pl.
   See Stamen.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Stamina \Stam"i*na\, n. pl.
   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.
      [1913 Webster]

   2. Whatever constitutes the principal strength or support of
      anything; backbone; vigor; as, the stamina of a
      constitution or of life; the stamina of a State.
      [1913 Webster]

            He succeeded to great captains who had sapped the
            whole stamina and resistance of the contest. --De
                                                  Quincey.
      [1913 Webster]

   3. Hence: The power of endurance; the ability to withstand
      fatigue, disease, deprivation, etc., and continue working.
      [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Stamen \Sta"men\ (st[=a]"m[e^]n), n.; pl. E. Stamens
   (-m[e^]nz) (used only in the second sense); L. Stamina
   (st[a^]m"[i^]*n[.a]) (in the first sense). [L. stamen the
   warp, a thread, fiber, akin to Gr. sth`mwn the warp, fr.
   'ista`nai to stand, akin to E. stand. See Stand, and cf.
   Stamin, Stamina.]
   1. A thread; especially, a warp thread.
      [1913 Webster]

   2. (pl. Stamens, rarely Stamina.) (Bot.) The male organ
      of flowers for secreting and furnishing the pollen or
      fecundating dust. It consists of the anther and filament.
      [1913 Webster]

WordNet (r) 3.0 (2006):

stamina
    n 1: enduring strength and energy [syn: stamina, staying
         power, toughness]