The word
eunuch does not derive, as one might think, from the operation that produced a eunuch but rather from one of his functions.
Eunuch goes back to the Greek word
eunoukhos, "a castrated person employed to take charge of the women of a harem and act as chamberlain." The Greek word is derived from
eune, "bed," and
ekhein, "to keep." A eunuch, of course, was ideally suited to guard the bedchamber of women.