Couverture: The technical name for the high-quality chocolate used to make confections and pastries, from the French couvrir, "to cover."
Ganache: Couverture is added to boiled cream to make the filling for many confections. Butter also is often used in the mixture. The ganache may be flavored by infusing the cream with various ingredients.
Single-origin, or varietal, couverture: Chocolate for use by confectioners that is made with cocoa beans from a particular growing region — maybe from a specific county or even from one estate.
Molded chocolates: Principally a Belgian technique in which a shell of chocolate is formed in a mold. A variety of fillings — butter cream, praline, caramel, ganache — can be poured or piped into the center. Then it's closed with more chocolate.
Enrobed chocolates: Enrobing is a more common technique, the way many French chocolates are made. The center is often a ganache that is fairly firm and can stand up to being coated with melted chocolate. Often you can tell a chocolate is enrobed by looking at the bottom, which will be flat with some excess around the edges.
Truffles: Hand-rolled balls of ganache, sometimes dipped in chocolate, often rolled in cocoa powder.