IPA: /ˌpriːˈklɪərəns/
KK: /priˈklɪr əns/
A process that allows individuals or goods to be approved for customs or immigration before they arrive at a border.
The travelers completed their preclearance at the airport to avoid delays upon arrival.
Preclearance → It is formed from "pre-" (meaning before) and "clearance" (from the verb "clear", meaning to remove or to free from). The word "preclearance" refers to the act of obtaining permission or clearance before an event or action takes place.
Think of getting permission or clearance 'before' ('pre-') something happens — that's what preclearance means.