Only found in Matthew 19:28 and Titus 3:5. This word literally means a "new birth." The Greek word so rendered (palingenesia) is used by classical writers with reference to the changes produced by the return of spring. In Matthew 19:28 the word is equivalent to the "restitution of all things" (Acts 3:21). In Titus 3:5 it denotes that change of heart elsewhere spoken of as a passing from death to life (1 John 3:14); becoming a new creature in Christ Jesus (2 Corinthians 5:17); being born again (John 3:5); a renewal of the mind (Romans 12:2); a resurrection from the dead (Ephesians 2:6); a being quickened (2:1,5).
This change is ascribed to the Holy Spirit. It originates not with man but with God (John 1:12,13; 1 John 2:29; 5:1,4).
As to the nature of the change, it consists in the implanting of a new principle or disposition in the soul; the impartation of spiritual life to those who are by nature "dead in trespasses and sins."
The necessity of such a change is emphatically affirmed in Scripture (John 3:3; Romans 7:18; 8:7-9; 1 Corinthians 2:14; Ephesians 2:1; 4:21-24).
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Regeneration'". "Easton's Bible Dictionary".