B1unwanted matter or material of any type, especially what is left after useful substances or parts have been removed: Britain produces 20 million tonnes of household waste each year.He opposes any kind of nuclear waste being dumped at sea.Millions of gallons of untreated human waste (= excrement) flow into the river every day.Oil spills are common, as is the dumping of toxic industrial wastes.The Japanese recycle more than half of their waste paper.Rubbish and wasteEnvironmental issues