A legal meaning. Must meet stringent standards to use the name as it’s protected from use outside the region.
Must be grown and produced in an area within a 5 hour drive southwest of Paris. Red Bordeaux must be made of Cabernet Sauvignon, Merlot, Cabernet Franc, Petit Verdot, or Malbac.
Almost always a blend with Cab or Merlot as the dominant grape. 90% of Bordeauxs are red.
Famous producers are, Chateau Haut Brion, Chateau Lafite Rothschild, Chateau Latour, Chateau Margaux. Can cost hunders or thousands of dollars. Plenty are available under $50 (though are still great).