Definition - What does Witnesseth mean?
Witnesseth means "to take notice of." This term is used interchangeably with the word "witness." Witnesseth is primarily used by members of the legal system, such as judges, lawyers, and clerks. It falls under the category of legal jargon. So a person who witnesseth something is a person who witnessed something.
Justipedia explains Witnesseth
Witnesses are very important to trials. Witnesses are called to the witness stand to provide a testimony about events they have seen or things that they know. A single witness who sees a crime take place can sometimes be the difference between a guilty or innocent verdict. So, those who "witnesseth" or take notice of things that are relevant to a trial can strongly help the case of either a plaintiff or a defendant.