An owner's certificate is a legal document that is used to prove ownership of a property. It is also known as a DEED, which is a four-letter word that can be used to solve the crossword puzzle. The owner's certificate is typically issued by a government agency or a court and contains information about the property, such as its location, size, and any restrictions that may apply. It also includes the name of the owner and any other parties involved in the transaction. The owner's certificate serves as proof of ownership and is required for any transfer of ownership or sale of the property.