These words refer to cast-off remains or leavings. Waste is the most general, referring to anything left over from some process, regardless of whether it can or cannot be used in some other process: bundling and selling the piles of newspapers as waste ; more sophisticated sewage plant to process human wastes ; pollution of rivers by industrial wastes. Refuse suggests an accumulation of broken or unusable objects, usually bulky ones: a once-limpid pool filled up with old tyres, tin cans and other refuse . Rubbish suggests a collection of less bulky items than refuse and may imply, as is not necessarily so with the former word, used-up remnants collected specifically to be disposed of: shoving sacks of rubbish into the incinerator. Sometimes rubbish is distinguished from refuse as being burnable, but this is not universally true. Garbage is the most specific of these words, referring almost exclusively to uneaten or inedible remains from the kitchen that must be disposed of before they spoil and become a sanitary problem. By contrast, rubbish does not imply the same necessity for disposal since it refers largely to incorruptible materials. In practice these three words are used fairly loosely for one another, and we may hear of garbage , rubbish , or refuse tins (or bins).

Pollutants refers specifically to motor or industrial wastes that are emptied into waterways or the air and result in the fouling of these elements: pollutants from the exhausts of cars and buses; chemical pollutants from a single factory that can kill thousands of fish annually. Debris refers to the random piling up or scattering of extremely bulky remnants or pieces of wreckage: a plane crash that scattered debris over half a mile; debris from the construction job that was never hauled away. It can be used like refuse for less sizeable items, but in this case it still implies a random or bit-by-bit scattering: debris carelessly tossed along the sides of our highways.

Junk and trash can both refer to worn-out or worthless cast-offs. In an industrial context, junk can refer to old cars and other large machines collected for the re-usable parts or metals in them. In a housekeeping context, junk can refer to smaller items of little or no value: broken teacups, jars of mismatched nuts and bolts, and other junk . Trash is close to refuse in its generality, but it suggests a collection of heterogeneous items of small size: After cleaning up the garage, we swept up the trash and put it in the garbage bin and hauled stacks of junk out of the tip.