It can also be related to the concept of "making liquid" or "becoming liquid".
Here are some examples of words derived from "fus":
* Fuse: To melt or become liquid, or to join things together by melting.
* Fusion: The process of melting or joining together.
* Diffuse: To spread out or scatter.
* Refuse: To reject or decline.
* Infusion: The act of steeping something in a liquid to extract its flavor or properties.