From the French carton, 'drawing', from the Italian cartone, 'pasteboard'. In English it became narrowed to humorous drawings, often with captions. It's probably a regional thing, but sometimes cartoons will be used for comics. There are also political cartoons for the (usually) single drawings on the editorial pages of many US newspapers. In my idiolect, cartoon refers to single panel comics; multipanel comics are comics, short for comic strips, where comic is acting adjectivally.