An open sweet or savoury tart is a type of pastry dish that can be filled with either a sweet or savoury filling. The term for this type of dish is 'FLAN', which is a four letter word that fits the crossword solution. FLAN is a French word derived from the Latin word 'flado' meaning flat cake. It is usually made with a pastry crust and can be filled with a variety of ingredients such as fruits, custards, cheeses, meats, vegetables, and more.