IPA: /θɜːrməlaɪˈzeɪʃən/
KK: /ˈθɜrməlaɪˌzeɪʃən/
The process of achieving a state where two or more objects have the same temperature through interaction.
The thermalization of the gas occurred quickly as it came into contact with the cooler walls of the container.
Thermalization is formed from "therm-" (from Greek "thermos", meaning heat) and "-alization" (a suffix indicating the process of making or becoming). The word refers to the process of becoming thermal or relating to heat.
Think of 'heat' ('therm-') and the process of 'becoming' ('-alization') to remember that thermalization means the process of becoming related to heat.