The Collaborative International Dictionary of English v.0.48:

Rounceval \Roun"ce*val\, a. [F. Ronceval, Roncevaux, a town at
   the foot of the foot of the Pyrenees, Sp. Roncesvalles.]
   Large; strong; -- from the gigantic bones shown at
   Roncesvalles, and alleged to be those of old heroes. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rounceval \Roun"ce*val\, n.
   A giant; anything large; a kind of pea called also
   marrowfat. [Obs.]
   [1913 Webster]