Thayer's Greek Lexicon

 1. a bed keeper, bed guard, superintendent of the bedchamber, chamberlain
  1) in the palace of oriental monarchs who support numerous wives
the superintendent of the women's apartment or harem, an office
held by eunuchs
  2) an emasculated man, a eunuch
1b1. eunuchs in oriental courts held by other offices of greater,
held by the Ethiopian eunuch mentioned in Ac. 8:27-39.
  3) one naturally incapacitated
1c1. for marriage
1c2. begetting children
  4) one who voluntarily abstains from marriage