"Pathogenic" means capable of causing disease. It is often used to describe microorganisms like bacteria, viruses, fungi, and parasites that can infect a host and lead to illness.

Here's a breakdown:

* Patho- comes from the Greek word "pathos," meaning "suffering" or "disease."

* -genic comes from the Greek word "genesis," meaning "origin" or "creation."

Therefore, pathogenic literally means "disease-creating."

Examples:

* Pathogenic bacteria: Bacteria like *Salmonella* and *E. coli* can cause food poisoning.

* Pathogenic viruses: The influenza virus causes the flu.

* Pathogenic fungi: Fungal infections like athlete's foot are caused by pathogenic fungi.

Important Note: Not all microorganisms are pathogenic. Many are beneficial or harmless to humans.