Easton's Bible Dictionary (1897)
(Gr. diabolos), a slanderer, the arch-enemy of man’s spiritual interest (Job 1:6; Rev. 2:10; Zech. 3:1). He is called also “the accuser of the brethen” (Rev. 12:10). In Lev. 17:7 the word “devil” is the translation of the Hebrew sair, meaning a “goat” or “satyr” (Isa. 13:21; 34:14), alluding to the wood-daemons, the objects of idolatrous worship among the heathen. In Deut. 32:17 and Ps. 106:37 it is the translation of Hebrew shed, meaning lord, and idol, regarded by the Jews as a “demon,” as the word is rendered in the Revised Version.
In the narratives of the Gospels regarding the “casting out of devils” a different Greek word (daimon) is used. In the time of our Lord there were frequent cases of demoniacal possession (Matt. 12:25-30; Mark 5:1-20; Luke 4:35; 10:18, etc.).
Smith's Bible Dictionary (1863)
(slanderer). The name describes Satan as slandering God to man and man to God. The former work is of course, a part of his great work of temptation to evil and is not only exemplified but illustrated as to its general nature and tendency by the narrative of Gen. 3.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
DEV'IL (slanderer). This word (from the Greek diabolos) is sometimes applied to very wicked men or women, John 6:70 (Judas Iscariot); Acts 13:10; 2 Tim 3:3; Tit 2:3, and translated "devil" or "false accusers," but usually it denotes the one most subtle and malignant of the evil spirits, and the great enemy of God and man. T. Matt 16:23; Mark 8:33; Luke 22:3. Satan can assume a character quite opposite to his real one, and hence he is said by Paul to transform himself into an "angel of light," 2 Cor 11:14. g. Matt 4:24. " It is common to call these afflicted people demoniacs.
Three views are held upon the demoniacal possessions: That the possession of the devil symbolizes the prevalence of evil in the world, the casting out of the devils by our Lord, his conquest over that evil power by his doctrine and his life. This theory of course gives up the historic character of the narratives. That the demoniacs were not really under the power of demons; but inasmuch as it was commonly believed they were, our Lord and the evangelists spoke to them and of them in this fashion.
They were merely persons suffering unusual diseases of body and mind, especially epilepsy, melancholy, insanity. The advocates of this view present three arguments:(1) The symptoms of the "possessed" were frequently those of bodily disease — dumbness. Matt 9:32; blindness. Matt 12:22; epilepsy, Mark 9:17-27 — or those seen in cases of ordinary insanity. Matt 8:28. (2) "To have a devil" seems to be equivalent to to be "mad," John 7:20; John 8:48; Num 10:20. (3) There is no such thing to-day as "demoniacal possession," but there are frequent cases similar to those recorded.
Hence the language is popular, and not exact. That there were persons actually possessed by demons — such possession manifesting itself in the forms of bodily and mental disease. Our Lord really cast out demons. This theory has in its support:(1) The plain meaning of the text. It is the most natural interpretation. The demons are plainly distinguished from the persons whom they possess; they have a separate consciousness; they know Jesus, and look forward with trembling to the judgment-day; they pass from one person to another, or even into a herd of swine.
(2) It accords with the Scripture notion of the malignity of Satan that he should make a special exhibition of his power against Jesus. (3) It explains the confessions of our Lord's divinity which imply superhuman knowledge. (4) It renders intelligible the crucial narrative of the man among the tombs, Mark 5:1-20. The other theories either deny the fact or give a forced interpretation. (5) It vindicates the truthfulness of Jesus, which the other theories impugn. He not only addressed the patients as "possessed," Luke 4:35, but distinctly linked demoniacal possession with the evil one.
Matt 12:25-30; Luke 10:18.