It's connected to the word "radix," which means "root" in Latin. This root appears in many English words, such as:
* Radical: Meaning "fundamental" or "extreme," referring to the root of something.
* Radicate: Meaning "to establish firmly," as if taking root.
* Radicule: The first root that emerges from a germinating seed.
* Radioactive: Relating to the emission of radiation from the nucleus of an atom, which is considered its "root."
So, whenever you encounter the word "radic" in an English word, remember it's referring to the root or the foundation of something.