Introduction:
The term virus is commonly used in modern society to refer to a type of infectious agent that can cause disease in humans, animals, and plants. However, the history of the word virus can be traced back to the late 19th century when it was first coined by a scientist named Dmitri Ivanovsky.

Dmitri Ivanovsky:
Dmitri Ivanovsky was a Russian scientist who was born in 1864 and died in 1920. He is best known for his work on the tobacco mosaic virus, which he discovered in 1892 while studying the disease that was affecting tobacco plants in Russia.

Discovery of Tobacco Mosaic Virus:
While studying the tobacco plant disease, Ivanovsky noticed that the sap from infected plants still contained the infectious agent even after being filtered through a porcelain filter that was known to remove bacteria. This led him to conclude that the infectious agent was something smaller than bacteria and required further investigation.

Identification of Virus:
Ivanovsky's discovery of the tobacco mosaic virus was groundbreaking and laid the foundation for the study of virology. However, it wasn't until the 1930s that scientists were able to isolate and identify viruses as entities separate from other infectious agents.

Coined the term Virus:
It was Ivanovsky who first used the term virus to describe the infectious agent that he had discovered. The word virus comes from the Latin word for poison or slimy liquid and was chosen by Ivanovsky to reflect the mysterious and elusive nature of the infectious agent he had discovered.

Conclusion:
In conclusion, Dmitri Ivanovsky was a Russian scientist who is credited with discovering the tobacco mosaic virus and coining the term virus to describe this infectious agent. His work laid the foundation for the study of virology and has had a profound impact on our understanding of infectious diseases.