What is fornication?
Fornication comes from the Greek word porneia (4202) and means (1):
1) illicit sexual intercourse
1a) adultery, fornication, homosexuality, lesbianism, intercourse with animals, etc.
1b) sexual intercourse with close relatives; Leviticus 18
1c) sexual intercourse with a divorced man or woman; Mark 10:11,12
2) metaph. the worship of idols
2a) of the defilement of idolatry, as incurred by eating the sacrifices offered to idols
There are 26 instances of the word porneia in Mat 5:32, 5:19, 19:9, Mat 7:21, John 8:41, Acts 15:20, 15:29, 21:25, Romans 1:29, 1Cor 5:1, 6:13, 6:18, 7:2, 12:21, Gal 5:19, Eph 5:3, Col 3:5, 1Th 4:3, Rev 2:21, 9:21, 14:8, 17:2, 17:4, 18:3, 19:2.
References:1. Blue Letter Bible
But that we write unto them, that they abstain from pollutions of idols, and from fornication, and from things strangled, and from blood.
That ye abstain from meats offered to idols, and from blood, and from things strangled, and from fornication: from which if ye keep yourselves, ye shall do well. Fare ye well.
As touching the Gentiles which believe, we have written and concluded that they observe no such thing, save only that they keep themselves from things offered to idols, and from blood, and from strangled, and from fornication.
Being filled with all unrighteousness, fornication, wickedness, covetousness, maliciousness; full of envy, murder, debate, deceit, malignity; whisperers,
It is reported commonly that there is fornication among you, and such fornication as is not so much as father's wife.
1 Corinthians 5:1
Meats for the belly, and the belly for meats: but God shall destroy both it and them. Now the body is not for fornication, but for the Lord; and the Lord for the body.
1 Corinthians 6:13
Flee fornication. Every sin that a man doeth is without the body; but he that committeth fornication sinneth against his own body.
1 Corinthians 6:18
Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband.
1 Corinthians 7:2
And lest, when I come again, my God will humble me among you, and that I shall bewail many which have sinned already, and have not repented of the uncleanness and fornication and lasciviousness which they have committed. 2 Corinthians 12:21
Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness,
But fornication, and all uncleanness, or covetousness, let it not be once named among you, as becometh saints;
Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry:
For this is the will of God, even your sanctification, that ye should abstain from fornication:
1 Thessalonians 4:3
And I gave her space to repent of her fornication; and she repented not.
Neither repented they of their murders, nor of their sorceries, nor of their fornication, nor of their thefts.
And there followed another angel, saying, Babylon is fallen, is fallen, that great city, because she made all nations drink of the wine of the wrath of her fornication.
With whom the kings of the earth have committed fornication, and the inhabitants of the earth have been made drunk with the wine of her fornication.
And the woman was arrayed in purple and scarlet colour, and decked with gold and precious stones and pearls, having a golden cup in her hand full of abominations and filthiness of her fornication:
For all nations have drunk of the wine of the wrath of her fornication, and the kings of the earth have committed fornication with her, and the merchants of the earth are waxed rich through the abundance of her delicacies.
For true and righteous are his judgments: for he hath judged the great whore, which did corrupt the earth with her fornication, and hath avenged the blood of his servants at her hand.