IPA: //priːˈɛstəb.lɪʃ//
KK: /priːˈɛstəbliʃ/
To set something up or arrange it in advance before it happens.
The committee decided to preestablish the rules for the event before the participants arrived.
Past: preestablished
Past Participle: preestablished
Preestablish → It is formed from "pre-" (meaning before) and "establish" (from Latin "stabilire", meaning to make stable or set up). The word means to set something up or make it stable before a certain time or event.
Think of 'before' ('pre-') setting something up ('establish') — that's why preestablish means to set something up in advance.