The term ENVELOPE FASTENER can be summarized as a CLASP, which is a five-letter word. A CLASP is a device used to secure an envelope or other item closed. It is typically made of metal and consists of two parts that are joined together by a hinge. Clasps are often used in place of traditional adhesive seals, such as glue or tape, to provide a more secure closure. Clasps are also commonly used to attach items to clothing, bags, and other items.