A nonimmigrant visa is a type of visa that allows foreign nationals to enter the United States temporarily for specific purposes, such as tourism, business, or study. These visas are designed for individuals who do not intend to stay permanently and must return to their home country after their authorized stay. There are various categories of nonimmigrant visas, including B-1 for business visitors, B-2 for tourists, and F-1 for students. Each category has its own requirements and limitations, ensuring that visitors comply with U.S. immigration laws during their temporary stay.