The porcelain bowl and tank attached to the floor of a bathroom, loo, or water closet can always be called a toilet. … In the strictest sense, a bedpan or portable toilet seat with an attached dry receptacle would be a commode, while the water-flushed bowl and tank in the bathroom would be a toilet.

In the United States, a “commode” is now a colloquial synonym for a flush toilet. The word commode comes from the French word for “convenient” or “suitable”, which in turn comes from the Latin adjective commodus, with similar meanings.