noun
1.
fundamental alteration in one's system of beliefs
Judaism does not encourage conversion of gentiles
Synonyms: metanoia, rebirth
Related Word: about-face, reversal, turning; reclamation, regeneration
Idioms: change of heart
2.
change of one thing to another usually by substitution
conversion of locomotives from steam to diesel power
Synonyms: alteration, changeover, shift, transformation
Related Word: change, modification, qualification; metamorphosis, mutation, permutation, transmutation; innovation, novelty