1st, 2nd, 3rd....growths on Left Bank in Bordeaux.
On the Right Bank, however St. Emilion has its own system with Premier Grand Cru Classe Class A, then Premier Grand Cru Classe Class B, then Grand Cru Classe, and the rest will likely say Grand Vin.
More confusing in Pomerol, as the excellent VCC (Vieux Chateau Certan) says' Grand Vin on label, (wouldn't be great in St. Emilion) and garagiste wine LePin that goes for $2k plus per bottle simply says Le Pin, Pomerol.
The French seem to like making you do homework before buying their wine, lol.
Tom Stevenson's Sotheby's Wine Encyclopedia is a good source for checking historical standing of French Chateau.