Like other things, the WTS has its own unique definition of this. ...We are talking about the Greek word porneia rendered as fornication in the New Testament .
Consider what the respected experts say
STRONGS
Fornication, Fornicator:
is used
(a) of "illicit sexual intercourse," in Jhn 8:41; Act 15:20,29; 21:25; 1Cr 5:1; 6:13,18; 2Cr 12:21; Gal 5:19; Eph 5:3; Col 3:5; 1Th 4:3; Rev 2:21; 9:21; in the plural in 1Cr 7:2; in Mat 5:32; 19:9 it stands for, or includes, adultery; it is distinguished from it in Mat 15:19; Mar 7:21;
(b) metaphorically, of "the association of pagan idolatry with doctrines of, and professed adherence to, the Christian faith," Rev 14:8; 17:2,4; 18:3; 19:2; some suggest this as the sense in Rev 2:21.
VINES
Fornication, Fornicator:
is used
(a) of "illicit sexual intercourse," it stands for, or includes, adultery; it is distinguished from it in Mat 15:19; Mar 7:21;
(b) metaphorically, of "the association of pagan idolatry with doctrines of, and professed adherence to, the Christian faith," Rev 14:8; 17:2,4;
However , The Watchtower makes these comments.
w06 7/15 pp. 29-30 Questions From Readers ***
Fornication
(Greek,
por·nei´a) applies to illicit sexual relations outside Scriptural marriage. It includes adultery, prostitution, and sex relations between unmarried individuals as well as oral and anal sex and the
sexual manipulation of the genitals of an individual to whom one is not married. A person who unrepentantly practices fornication does not belong in the Christian congregation.
*** w04 2/15 pp. 13-14 par. 15 Maintain Chastity by Safeguarding Your Heart ***
The Greek word por·nei´a, translated "fornication," has a fairly broad meaning. It relates to sexual relations involving persons not married to each other and focuses on the misuse of the sexual organs. Por·nei´a includes such acts as oral sex, anal sex, and masturbating another person—conduct commonly associated with houses of prostitution. People who think that such acts are not "fornication" are fooling themselves and have fallen victim to one of Satan’s snares. (2 Timothy 2:26) Furthermore, maintaining chastity means more than merely refraining from any act that constitutes fornication. To "flee from fornication," we must avoid all forms of sexual uncleanness and loose conduct that could lead to the gross sin of por·nei´a. (Ephesians 4:19) In that way we maintain chastity
So a spot of passionate fumbling in nether regions is fornication in the unique 'dictionary' that is known only to the J W - but not to the rest of the world
