Pyrena :: Pyrena (n.) A nutlet resembling a seed, or the kernel of a drupe..
Pyrene :: Pyrene (n.) One of the less volatile hydrocarbons of coal tar, obtained as a white crystalline substance, C16H10..
Pyrenean :: Pyrenean (a.) Of or pertaining to the Pyrenees, a range of mountains separating France and Spain..
Pyrenoid :: Pyrenoid (n.) A transparent body found in the chromatophores of certain Infusoria.