Self-addressed is a term commonly used when referring to an envelope or letter that includes the sender's address. However, there are a few other words that can be used interchangeably with self-addressed. The term pre-addressed is often used when referring to envelopes or letters that already have the sender's address on them. Additionally, you could use the phrase return address or sender's address to refer to the same thing. Finally, the term addressed can also be used to describe an envelope or letter with the sender's address. While these words may have slightly different connotations, they can all be used in place of self-addressed.