Actually "theocracy" means "God rules" and that concept is in the Bible and is not exclusively used by the WTS.
It might be better to use the word "governing body" in this discussion because the WTS itself admits that this term doesn't appear in the Bible. The term "governing body" does not appear as a major section in the Insight Volume because the term is not scriptural.
*** w72 11/15 pp. 703-704 Questions From Readers ***
Why do we use the term "governing body" for the elders that preside over the work of Jehovah’s witnesses?—U.S.A.
The term "governing body" as such is not found in the Scriptures. However, there is ample evidence that a body of elders serving in a governing capacity did exist in the first-century Christian congregation.
Paul admonished his fellow Christians: "Remember those who are takingthelead among you. . . . Be obedient to those who are takingthelead among you and be submissive." Or, as other translations put it, remember and obey ‘those guiding you.’ (AuthorizedVersion, margin; Murdock’s Syriac;Rotherham) The KingdomInterlinear reads: "Be you mindful of the ones governing [Gr., he·gou·me´non] of you."—Heb. 13:7, 17, 24.
Forms of this same Greek word are found at Matthew 2:6; Luke 22:26; Acts 7:10; 15:22, where the meaning is similar, namely, that of governing, acting as chief or taking the lead. The Septuagint uses a form of this word in rendering Malachi 1:8: "Bring it near, please, to your governor [Gr., he·gou·me´noi]."
Thus, it is evident that there were certain persons governing in the Christian congregation by the lead and guidance they gave their brothers in righteous works and godly principles.
The English word "govern," from the Latin verb gubernare, is derived from the Greek word ky·ber·na´o, which has the basic meaning to "steer or pilot a ship, direct, govern." (CenturyDictionaryandCyclopedia, Vol. III, pp. 2584, 2585) For this reason a "governor" may refer to the mechanism on a machine that controls and regulates its speed or pressure. A "governing body" may, therefore, refer to an agency that administers policy and gives direction, guidance and regulation to an organization.
Commenting on the Greek word from which the English "govern" comes, the ExpositoryDictionaryofNewTestamentWords by W. E. Vine (Vol. II, p. 168) says: "kubernao, to guide (whence Eng., govern), denotes (a) steering, pilotage [compare Acts 27:11]; (b) metaphorically, governments or governings, said of those who act as guides in a local church, 1 Cor. 12:28." This text, 1 Corinthians 12:28, reads: "And God has set the respective ones in the congregation, first, apostles; second, prophets; third, teachers; then powerful works; then gifts of healings; helpful services, abilities to direct [Gr., ky·ber·ne´seis]."
The Septuagint, in translating the Hebrew word tahh·bu·lah´, meaning ‘steerage, guidance,’ uses this Greek word, as, for example, at Proverbs 1:5: "The man of understanding will gain direction [Gr., ky·ber´ne·sin]."
In the first century, the elders and overseers in the various congregations certainly exercised "abilities to direct" in the local territories, as this was necessary for good coordination of the work and for peace and unity in the flock of God. Directive guidance is an essential part of the work of a shepherd.—Compare Acts 20:17, 28; 1 Timothy 3:4, 5; Titus 1:9.
And what was true of the local congregations was clearly necessary for the directing of the Christian work in general. So it was that the apostles and other elders in Jerusalem served as a body to give guidance and counsel to all the congregations.
While "abilities to direct" are placed considerably down the list of the ‘varieties of ministries and gifts’ that God provided (1 Cor. 12:4, 5, 28), yet such abilities were not inconsequential, otherwise they would not have been bestowed on the apostles and older men forming the governing body. How these men acted as a body is evident in the way they resolved the problem of food distribution by appointing a committee of qualified men to care for the matter; by their dispatching of Peter and John to Samaria to aid the new disciples there; by their action, as a body in conjunction with other elders, in sending out four "leading men," including the apostle Paul, to carry to Antioch their decision regarding the Gentile converts to Christianity; and by their counseling Paul as to the procedure he should follow among the Jews in Jerusalem.—Acts 6:1-6; 8:14; 15:1, 2, 22-32; 21:17-26.
The resurrected Jesus Christ is the heavenly Governor of his congregation of spiritual Israelites on earth. He is the one to whom the words quoted from Micah 5:2 apply: "And you, O Bethlehem of the land of Judah, are by no means the most insignificant city among the governors of Judah; for out of you will come forth a governing one [Gr., he·gou´me·nos], who will shepherd my people, Israel." (Matt. 2:6) By means of holy spirit and by the visible governing body composed of elders "governing" or "taking the lead" (Gr., he·gou·me´non) according to God’s written Word, Jesus Christ governs the worldwide group of Jehovah’s witnesses on earth today.—Heb. 13:17, Interlinear; also NewWorldTranslationoftheChristianGreekScriptures, of 1950.
From this we see that the term "governing body" is as appropriate, fitting and Scriptural as any for referring to that body of elders entrusted with the spiritual oversight of Jehovah’s Christian witnesses today.