Each of the pair of reproductive organs of male reptiles, which use only one in each copulation.
In Biology it is the name given to each of the two sexual organs possessed by the squamous male reptiles (lizards, snakes). Etimologically it would mean half penis or half, but this simply is because they possess two limbs.
HEMIPENE of hemi , Greek prefix meaning medium , half . Sarcastic term to represent a ridiculously small penis.