IPA: /ɪˌmoʊbɪlaɪˈzeɪʃən/
KK: /ɪˌmoʊbɪlaɪˈzeɪʃən/
The act of stopping something from moving or making it unable to move.
The immobilization of the injured leg was necessary for proper healing.
Immobilization is formed from "in-" (meaning not) and "mobilis" (meaning movable) combined with the suffix "-ation" (indicating the action or process of). The word refers to the process of making something not movable or fixed in place.
Think of 'not' being added to 'movable' — that's why immobilization means making something not able to move.