Truffle versus chocolate
Chocolate is made from cocoa mass, sugar, cocoa butter, vanilla, and usually lecithin as an emulsifier. Chocolate is an ingredient used to make truffles.
A truffle is a generic name for a confection. Other words for truffles include praline (pray-lean, used in Belgium) and bon bon (used the US). When the final e in praline is accented it refers to a paste of roasted nuts (usually almonds or hazelnuts) ground finely with caramelized sugar. Almonds simply covered with caramelized sugar are referred to as praslins after the name of the duke whose cook accidentally invented them - Cesar Choiseul, comte Du Plessis-Praslin.
There are several basic styles of truffles. There is the truffe nature, which looks like the fungus, which lent its name to the chocolate delicacy. In the truffe nature, the ganache center is the support for the chocolate enrobing. (This technique is used by many "truffles.")
Ganache, in its purest form, is a mixture of chocolate and cream. Ganaches can contain sugar (in the form of liquid glucose), butter, and flavorings.
Another form of truffle uses hollow molded chocolate shells. These shells can be filled with many different types of centers, including ganache, praline, caramel, alcohol, etc. and are then sealed with a chocolate bottom.