The term 'stamp of approval' is a phrase that is used to describe an official ENDORSEMENT or sign of approval. The crossword solutions for this term are SEAL, PAID, ENDORSEMENT, and USDA. SEAL is a wax or adhesive stamp that is used to close an envelope or document. PAID is a term used to indicate that a payment has been made. ENDORSEMENT is a formal statement of support or approval. Finally, USDA stands for the United States Department of Agriculture, which is a federal agency responsible for developing and executing agricultural policy.