Waste (n) – garbage, trash or litter.
Wastewater (n) – water that becomes dirty from human use,
either from domestic or industrial uses.
Water (n) – a clear, odorless, tasteless liquid that is the
main part of all living things.
Water cycle (n) – the process by which water on the Earth is
evaporated into a vapor (gas), condenses into a liquid in clouds,
and falls back to Earth as precipitation.
Watershed (n) – an area of land that acts as a basin by
draining all water falling or flowing within it to a certain river
or lake; also called a recharge basin.
Wave (n) – a surge of water that is caused by wind or gravity.
Weather (n) – the state of the atmosphere with respect to heat
or cold, wetness or dryness, calm or storm, clearness or cloudiness.
Well (n) – a hole dug in the Earth that is generally used to
pump underground water.
Wetlands (n) – an area of land that is saturated with water or
covered with a shallow layer of water.
Wind energy (n) – a renewable source of energy that comes from
Wildlife (n) – animals that are not tamed.