IPA: /ˌdiːaɪənaɪˈzeɪʃən/
KK: /diˌaɪənaɪˈzeɪʃən/
The process of removing ions from a substance, usually a liquid, to make it neutral or pure.
Deionization is commonly used in water purification systems to produce high-quality water.
Deionization is formed from "de-" (meaning removal or reversal) and "ion" (from Greek "ion", meaning going or to go, referring to charged particles) and "-ization" (meaning the process of making or becoming). The word describes the process of removing ions from a solution, effectively reversing the presence of charged particles.
Think of 'removing' ('de-') charged particles ('ion') from a solution — that's what deionization means.