Literally "rough river." It is the name given to the Rio Grande in Hispanophone (Spanish-speaking) countries.
"By 1602, Rio Bravo had become the standard Spanish name for the lower river, below its confluence with the Rio Conchos."
"Early American settlers in south Texas began to use the modern 'English' name Rio Grande. By the late 19th century, in the United States, the name Rio Grande had become standard in being applied to the entire river, from Colorado to the sea."