From BiblePortal Wikipedia

Hastings' Dictionary of the New Testament [1]

The primitive Aryans worshipped a deity named, from ἀπέλλα, ‘the fold,’ Ἀπέλλων or Ἀπόλλων, ‘he of the fold,’ the special god of the cattle-pen, the patron deity of cattle-rearing. He was also called Αύκιος, ‘he who frightens away the wolf.’ As Φοῖβος, the sun-god, was the deity who opened the ἀπέλλαι (‘cattle-pens’) in the morning and drove out the herds, the one god became identified with the other. Apollo dwelt in caves._ Certain tribes of Aryan Hellenes who invaded and conquered what is now called Greece brought with them their cave-dwelling deity. One of these tribes settled in a narrow vale shut in between Mount Parnassus and Mount Cirphis. The place, afterwards called Delphi, was then named Πυθώ or Πύθων. In Πύθων was a cavern which emitted vapour of a more or less mephitic character. To the autochthons this was clear evidence of the presence of a chthonian spirit, most probably nameless, whom they worshipped. The cults of the two cave-dwellers inevitably amalgamated, and Apollo took the place of the nameless chthonian spirit and was called Πύθιος._ The name Πύθων is in some way connected with πύθειν, ‘to rot.’ Such a cave in primitive times was certain to have been a resort of serpents, and an aetiological myth arose to the effect that the cavern, which had been possessed by Themis, had been guarded by an immense serpent called Πύθων who was the offspring of Gaia, produced from mud after the flood of Deucalion. Four days after his birth Apollo, the child of Zeus and Leto, killed the serpent, from whom he took the name, its carcass being allowed to rot where it was killed._

Cattle-rearing being the chief employment of the earlier Aryans and Apollo being the protector of the fold, we can understand how helpfulness became one of his characteristics. This developed along two lines. (1) He suggested means by which calamities might be avoided. This led (2) to the conception of a power of prediction. In this way Apollo became the prophet of Zeus. Plato calls him ‘the interpreter of religion to all mankind.’_ His oracle made Delphi particularly famous,_ he became the most typical representative Hellenic deity, and his oracle at Delphi the most powerful influence in guiding and moulding the growth of Hellenism._ At Delphi his cult and oracle-giving became recognized and organized institutions. The oracle in historic times was of the ecstatic, enthusiastic, or epileptic kind. The chief agent was the Πυθία (the fem. of Πύθιος). When an oracle was asked, she, after preparation, drank the water of the sacred stream, chewed the leaves of the sacred laurel, mounted a tripod above the cavern from which the mephitic vapour arose, and then began to speak. Near her were the ὅσιοι, five priests who listened and interpreted her sayings._ Thus the Πυθία, a virtuous woman, became a mere tool in the hands of the Holy Ones, whose power has been aptly compared to that of the prophet Samuel._ Apollo had the power of communicating this gift of oracle-giving to others besides the Πυθία._ Persons who were ventriloquists, in the original sense of that term, would naturally be supposed to have had it conferred on them. Hence Πύθων meant equally the divine being and the person whom it possessed. These ἐγγαστρίμυθοι were apparently very common throughout the countries where Greek influence predominated. They were called Eurykleidai, Sternomanteis, and Pythones.

Such diviners belonged to the lowest grade of the profession and were evidently for the most part ventriloquists._ One such is brought before us in  Acts 16:16-18, in the Greek city of Philippi, during a visit paid to it by Paul and Silas. She was not a priestess of the Pythian Apollo, or in other words an accredited agent of the Delphic Oracle, as has been supposed,_ but a female slave, probably a ventriloquist, afflicted with lunacy of a mild chronic type,_ whose peculiarity was, according to the ideas of the time, looked upon as caused by her being possessed with a Pythonic spirit._ She was accordingly consulted by those who desired to have the future revealed to them, a business which produced a considerable revenue. She was not a slave mantic owned and exploited by a syndicate, as has often been stated,_ for οἱ κύριοι does not mean ‘masters’ but rather, as A. Souter has pointed out, the girl’s master and mistress._ These dealt with her cries as the ὅσιοι did with the deliverances of the Delphic priestess, framing out of them answers to those who consulted the girl.

For the Patristic view see Hermas, Mand. 11.

P. A. Gordon Clark.

Hastings' Dictionary of the Bible [2]

PYTHON . In   Acts 16:16 we read of a young girl at Philippi who had ‘a spirit, a Python’ (this is the reading of all the best MSS). Pytho was a district close to Delphi; and Python was the serpent at that place slain by Apollo, who therefore was called ‘the Pythian.’ Hence the priestess at Delphi was called ‘the Pythian.’ This seems to be the connexion of the name with divination. Plutarch says that ventriloquists in his day (1st cent. a.d.) were called ‘Phythons.’ Their powers were considered to be due to spiritual influence, and to include prediction. The girl at Philippi, then, was probably a ventriloquist, who brought her masters gain by sootbsaying. She proclaimed aloud for many days that Paul and his companions were slaves of the Most High God, and the Apostle at last drove out the spirit ‘in the name of Jesus Christ.’ Her masters thereupon, having lost their source of profit, denounced Paul and Silas to the magistrates.

A. J. Maclean.

Webster's Dictionary [3]

(1): ( n.) Any species of very large snakes of the genus Python, and allied genera, of the family Pythonidae. They are nearly allied to the boas. Called also rock snake.

(2): ( n.) A diviner by spirits.

International Standard Bible Encyclopedia [4]

pı̄´thon  : Occurs only in   Acts 16:16 , where the Revised Version (British and American) reads, "a certain maid having a spirit of divination (margin "a spirit, a Python") met us." Πύθων , Púthōn , or Πυθώ , Puthṓ , is the oldest name of Delphi (or the country about Delphi), in which was situated the famous Delphic Oracle. Consequently "Pythian spirit" came to be the generic title of the supposed source of inspiration of diviners, including the slave-girl of the account in Acts. Exactly what facts underlie the narrative it is rather hard to say, but it is evident that the girl was sincere in her conviction that she spoke with Pythian inspiration. Probably she represents some hysterical type, of none too strong mentality, whose confused utterances were taken as coming from some supernatural power. Impressed by Paul's personality, she followed him about, and, when his command came, was in a state of mind that had prepared her to obey it. The narrative, incidentally, gives an interesting sidelight on a society in which a girl with hysteria had a greater commercial value than she had after her cure. See Divination .

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [5]

occurs in the margin of  Acts 16:16, a Spirit Of Python , where the text of the A. V. reads a Spirit Of Divination. The word Python ( Πύθων in Greek mythology) is the name of a serpent, or dragon slain by Apollo, then transferred to Apollo himself; in later times used for Diviners , Soothsayers , held to be inspired of the Pythian Apollo (Plutarch, De Delect.; Orac. c. q.). The Pythones, like the obolth, "familiar spirits," among the idolatrous Hebrews ( Leviticus 19:31;  1 Samuel 28:3;  1 Samuel 28:7-9), were called Ventriloquists because the god or spirit was supposed to be in them, and to speak from their bellies without any motion of the lips. (See Necromancy).

The Nuttall Encyclopedia [6]

In the Greek mythology a serpent or dragon produced from the mud left on the earth after the deluge of Deucalion, a brood of sheer chaos and the dark, who lived in a cave of Parnassus, and was slain by Apollo, who founded the Pythian Games in commemoration of his victory, and was in consequence called Pythius.