What is the difference between plumbing and piping?

Plumbing is a general term for someone who works with or has reference to sewerage or water works. This includes installation and maintenance of all plumbing appliances, for example, toilets, baths, basins, geysers, waste stacks, water mains and drainage.

Piping as far as i know is not a job, but could refer to someone who installs and maintains piping to a factory or manufacturing plant.