Taken from John 10:16 (“I have other sheep that are not of this sheep pen. I must bring them also. they too will listen to my voice, and ther shall be one flock and one shepherd.”)
In the early 1930s, Jehovah’s Witnesses began to link the other sheep in John 10:16 with the great crowd of Revelation 7:9. The great crowd are viewed by Jehovah’s Witnesses as those who live through the great tribulation and on into the Millenium without dying where the other sheep includes the great crowd as well as others who are resurrected after Armageddon.
(Work on this term is still in progress)