Is there sonic difference between "regeneration" and "new birth"? The former occurs only twice in the Greek New Testament. "In the regeneration when the Son of man shall sit in the throne of His glory." Matt. 19:28. Here the word obviously refers to the new order of things which shall be obtained when our Lord Christ takes the kingdom. We could not apply the term "new birth, in this case.
Again in Titus 3:5 we read of "the washing of regeneration." Here we have the action of the word and Spirit of God, communicating a new nature, cleansing, renewing, and giving us our place in that new order of things, of which "regeneration" is the forcible expression. It evidently would not do to say, "The washing of the new birth" inasmuch as there is something implied in "regeneration" which is not in "new birth." No doubt there must be the new birth in order to have our place and portion in the new order of things. But we must ever remember that in the Scriptures there is never a distinction without a difference. and you will at once grasp the difference between "the new birth" and "the new order of things.”
The literal meaning of the word palingenesis, is "Genesis again." The old creation passed away and the new creation established on the ground of accomplished redemption.
As to the term "conversion," it only occurs once in the New Testament, in Acts 15:3, "declaring the conversion of the Gentiles." It means a turning to, or turning back and may be applied to the new birth of a soul, or to the restoration of a wanderer or a fallen one.