This should break down all of the french butter terms for you
Beurre: French for Butter.
Beurre blanc: French for white butter. Delicate sauce made from shallots, white wine, vinegar and butter.
Beurre Manie: a thickener made by combining 2 tablespoons butter with 2 tablespoons all-purpose flour and formed into small balls. A thick, buttery paste will result.
Beurre Noir: French for black butter. Butter cooked to a dark brown, not black; traditionally flavored with capers and an acid such as lemon or vinegar.
Beurre Noisette: French for brown butter; Made by melting butter until it turns a light brown.