SASE, FOR EXAMPLE is an acronym that stands for 'Self-Addressed Stamped Envelope'. It is a pre-addressed and pre-stamped envelope that is sent along with a letter or other document to ensure that the recipient can easily return the document. The acronym ENC (3 letters) stands for 'ENCLOSED' and ENCL (4 letters) stands for 'ENCLOSURE', which are both terms used to indicate that something is included in the envelope.