The term 'They're Shut at Night' can be solved by the crossword solution 'Eyelids', which is a 7 letter word. Eyelids are thin folds of skin that cover and protect the eyes. They are important for keeping out dust and other particles, and they also help regulate the amount of light that enters the eye. During the day, eyelids are open, allowing us to see, but at night, they close to help us sleep.