Waste

Waste inside a wheelie bin

Waste is used, discarded, and unwanted materials. One also speaks of trash, garbage, rubbish, or junk.

There are a number of different types of waste. It can exist as a solid, liquid, or gas or as waste heat. When released in as a liquid or gas the wastes can be referred to as emissions. It is usually strongly linked with pollution.

Waste may also be something that you cannot touch as wasted time or wasted opportunities. The term waste implies things which have been used inefficiently or inappropriately.