Easton's Bible Dictionary (1897)
Literally bed-keeper or chamberlain, and not necessarily in all cases one who was mutilated, although the practice of employing such mutilated persons in Oriental courts was common (2 Kings 9:32; Esther 2:3). The law of Moses excluded them from the congregation (Deut. 23:1). They were common also among the Greeks and Romans. It is said that even to-day there are some in Rome who are employed in singing soprano in the Sistine Chapel. Three classes of eunuchs are mentioned in Matt. 19:12.
Smith's Bible Dictionary (1863)
“The English form of the Greek word which means bed-keeper . In the strict and proper sense they were the persons who had charge of the bed-chambers in palaces and larger houses. But as the jealous and dissolute temperament of the East required this charge to be in the hands of persons who had been deprived of their virility, the word eunuch came naturally to denote persons in that condition. ” -Abbott.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
EU'NUCH (bed-keeper, chamberlain). Such persons have long been, and are still, employed about Eastern courts as guards and attendants in harems. 2 Kgs 9:32; Esth 2:3; and others of this class hold oftentimes the principal offices. They are often cowardly, jealous, intriguing, the tool of despots and libertines, ready for any evil work, being shameless and remorseless. They are also peculiarly liable to be melancholy, and, as the only way of ridding themselves of the burden of life, to commit suicide. Eunuchs are the natural consequence of polygamy, and they are numerous in the Eastern cities.
In ancient Rome there were many; so in Greece during the Byzantine period. There are even to-day in Rome a few who sing soprano in the Sistine chapel — the only instance in Christian lands. According to the law of Moses, no eunuch could enter into the congregation of the Lord, Deut 23:1; nor could a mutilated animal be offered in sacrifice. Lev 22:24. Eunuchs existed in the various foreign courts of which we read in the Bible. Herod had them, and so Queen Candace. Acts 8:27. The word "eunuch " is employed by Christ, Matt 19:12, in various senses to designate: 1.
Those who are naturally incapacitated; 2. Those who have been mutilated; 3. Those who voluntarily abstain from marriage in order to devote themselves more exclusively to the interests of the kingdom of God.