It means whoever you wrote the check to cashed it inside a bank. The person cashing the check had the amount in his/her account to cover it and didn't deposit it waiting for it to clear.
When a check is cashed at the bank, there is information the bank prints on the back of the check. The information includes the date and the bank and routing number of where the check was cashed.
If a person loses a cashier's check, they can inquire about the cashier's check at the bank where it was drawn. The bank will research to find out if the check was cashed, and who cashed it. In some cases, a refund will be issued for the check if it was never cashed, but this will take a number of weeks.
No.
A cashier's check is not a cancelled check unless it has been cashed. A cancelled check is one that has already been cashed. Once you cash a cashier's check, the bank keeps it and you don't get it back. If you write a personal check, once it is cashed, that check will come back to you in your statement as the physical item which will be a cancelled check - or you will get an image of the cancelled check.
A cashed check is commonly referred to as a "cleared check." This term indicates that the funds have been transferred from the payer's bank account to the payee's account, and the transaction has been completed. Once a check is cashed or cleared, it is no longer considered valid for future transactions.