Meaning

verb cause to change; make different; cause a transformation

verb become different in some particular way, without permanently losing one's or its former characteristics or essence

verb make an alteration to

originFrom Old French alterer (French altérer), from Medieval Latin alterāre (“to make other”), from Latin alter (“the other”), from al- (seen in alius (“other”), alienus (“of another”), etc.; see alias, alien, etc.) + compar. suffix -ter.

Etymology from Wiktionary, CC BY-SA 3.0