Writing one's name on something is a common practice that is used to signify ownership or agreement. Signing one's name is a way of verifying that the person has read and agreed to the terms of a document or contract. It is also a way of showing that the person is responsible for the contents of the document. Signing one's name is often done with a pen, but it can also be done electronically. The four-letter word for this action is 'SIGN'.