PP, PET, PVC... What do these acronyms for plastics mean?

Polypropylene, or PP, is the most widespread plastic in the world (16 percent), developed in the mid-1950s and used for automobile parts and food packaging as well as disposable trays. — Photo: Anson_iStock / Getty Images, via ETX DailyUp

Plastics are all around us – from food packaging and drinking bottles to the insulation in our homes.

They are mostly all derived from fossil fuels like oil and natural gas, but what are the key differences between each type of plastic?