A more thorough explanation:

Definition: Witnesseth is a legal term that means "to witness" or "to take notice of." It is often used in contracts to make them look more formal.

For example, a contract might begin with the phrase "This agreement witnesseth that..."

The use of "witnesseth" has declined over time, but it is still used in some legal documents.

Example:

A contract for the sale of a house might begin with the phrase "This agreement witnesseth that the seller agrees to sell the house to the buyer for the sum of $500,000."

This example illustrates how "witnesseth" is used to indicate that the parties involved in the contract have witnessed and agreed to the terms outlined in the document.