The crossword solution for the term MOUTH TOP is ROOF, which is a four-letter word. A ROOF is a structure that covers the uppermost part of a building or other structure, providing protection from the elements such as rain, snow, and sun. Roofs are typically made of materials such as metal, wood, tile, or asphalt shingles. The shape of a ROOF can vary greatly, depending on the style of the building and the climate in which it is located.