A hyperboloid is a type of three-dimensional geometric shape characterized by its hyperbolic cross-sections. There are two types: the hyperboloid of one sheet and the hyperboloid of two sheets. The one-sheet hyperboloid resembles a cooling tower or an hourglass, while the two-sheet hyperboloid consists of two separate "lobes." Hyperboloids are often studied in mathematics and used in various fields, including architecture and engineering, due to their unique structural properties.