epididymis

noun

Etymology: From Ancient Greek ἐπιδιδυμίς (epididumís), from ἐπί (epí, “upon, over”) + δίδυμος (dídumos, “twin; testicle”).

1. A narrow, tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens, where sperm are stored during maturation.

   “Most men, I daresay, have never heard of their epididymis.”