The crossword solution for the term 'Part of a Mouth' is 'ESTUARY', which is a seven-letter word. An ESTUARY is a partially enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries are important habitats for many species of fish, birds, and other wildlife. They are also important for human activities such as fishing, transportation, and recreation.