noun Ba·rack (Hus·sein), Jr. [buh-rahk hoo-seyn] /bəˈrɑk huˈseɪn/, born 1961, 44th president of the U.S. since 2009. nounBarack (Hussein) (bəˈrɑːk). born 1961, US Democrat politician: 44th president of the US from 2009