1734, "to render neutral" (in a chemical sense), from French neutraliser (17c.), from neutral (see neutral (adj.)). Meaning "to counterbalance, to kill by opposing" is from 1795. Related: Neutralized; neutralizing.
(n'trə-līz') To cause an acidic solution to become neutral by adding a base to it or to cause a basic solution to become neutral by adding an acid to it. Salt and water are usually formed in the process.