The crossword solution for the term 'HOOVER IS ONE' is DAM, which stands for a barrier built across a river to control the flow of water. The DAM is typically used to generate hydroelectric power, provide water for irrigation, and prevent flooding. The Hoover DAM, located on the Colorado River between Arizona and Nevada, is one of the most famous dams in the world. It was constructed in the 1930s and is named after President Herbert Hoover.