In the fortune-telling system, we want to use metal, water, wood, fire and earth as the five elements to explain everything. Metal stands for mineral, gold, jewelry, iron, rock or something hard. Water stands for liquid or something cold. Wood stands for tree or something to do with wood. Fire stands for Sun, fire, heat, light or something hot.
Earth stands for soil, dust or ground.
There are affinity and enmity relationships between five elements. The affinity relationship means supporting, helping, producing, etc. Wood can help Fire to burn. Metal can hold Water. Wood can release the power of Water.