Fore deep – a deep Earth crust downfall emerging at the boundary of platforms and geosynclines at the orogenic stage (e.g., Pre-Urals, Pre-Carpathian, Pre-Himalayas).

Such downfalls are filled with molasse formation deposits (marine in the lower part, lagoon in the middle and continental in the upper part). Fore deeps are sharply asymmetrical. In the process of their development their axes usually shift towards the platform. Coal and natural salt deposits, as well as oil and gas fields are associated with fore deeps.