Therefore, any word with the prefix "hydro-" is likely related to water in some way.
Here are some examples:
* Hydrant: A pipe with a valve that supplies water.
* Hydroelectric: Relating to the generation of electricity by water power.
* Hydrophobic: Repelling or tending to not mix with water.
* Hydrophilic: Attracting or tending to mix with water.
* Hydrology: The study of water and its movement on, in, and above the Earth.