The chocolate truffle owes its name to the underground fungus celebrated as a delicacy in French haute cuisine. Truffle comes from the Latin word tuber, meaning “swelling” or “truffle.” In English, tuber means “a short, thick, round stem that is a part of certain plants (such as the potato), that grows underground, and that can produce a new plant.” The chocolate version, defined as “a candy made of chocolate, butter, sugar, and sometimes liqueur shaped into balls and often coated with cocoa,” got its name from its resemblance to its namesake.
Truffle comes directly from the French word truffe, which, in addition to the fungus and the candy meanings, can be used in informal language to refer to a large nose or the tip of the muzzle of a dog or cat. It’s also a slang synonym for “idiot” or “imbecile.”
Though there’s not a formal distinction, chocolate truffles are typically soft, whereas a soft chocolate center covered in a hard chocolate shell is typically called a bonbon.