The term SHUTS SECURELY can be summarized by the crossword solution SEALS, which is a five-letter word. Seals are used to close off an area or container in order to keep it secure. Seals are often used to protect documents, packages, and other items from tampering or theft. They are also used to prevent water or air from entering or leaving a space. Seals are made of various materials, including rubber, plastic, and metal.