Infusion

Infusion is the process of getting plant chemicals into a solvent such as water, oil or alcohol. 
The flavours from plant material get into the solvent by putting in the plant material and letting it stay there for quite a time. This is known as steeping the material. An infusion is also the name for the resulting liquid. 
The process of infusion is different from decoction, which is boiling the plant material, or percolation, in which the water goes through the material (as in a coffeemaker.