Glossary of gardening terms -W:

Watering
To supply dry land with water by means of pipes, streams, or ditches

Watering Can
A watering can is a portable container, usually with a handle and a spout, used to hand water plants.

Weather Vane
A weather vane, also called a wind vane, is a movable device attached to an elevated object such as a roof for showing the direction of the wind. Very often these are in the shape of cockerels and are called weather cocks. Arrows are also popular, but a multitude of designs have been used.

Wettable powder
Finely ground pesticide that can be mixed in water and sprayed onto plants.

Whorls
Three or more leaves, branches or flowers that grow in a circular formation from a joint or node.