Pyrena or pyrene is the name for the stone within a drupe or drupelet. It consists of a seed surrounded by hard endocarp tissue. ... Found on http://en.wikipedia.org/wiki/Pyrena
Py·re'na noun ; plural Pyrenæ . [ New Latin , from Greek ..., the stone of fruit.] (Botany) A nutlet resembling a seed, or the kernel of a drupe. Gray. Found on http://www.encyclo.co.uk/webster/P/203