Disease names can reveal a lot about the history of medicine. The roots of the terms we know today often relate to older ideas about the cause of disease—from the position of the stars to "bad air"—or to ideas about how disease symptoms manifested. Below are the meanings behind 9 common (and thankfully not-so-common) diseases:

1. CHICKEN POX

The medical name for chicken pox is varicella, which is derived from the Latin word variola, meaning speckled or spotted. Etymologists are not certain why the disease is colloquially known as chicken pox; some think it is because it is a lesser (or chicken as in "chicken-hearted") disease compared to smallpox (which itself was named to differentiate it from the "great pox," a.k.a. syphilis). Others think it comes from the old English for "to itch" – "giccan," which said out loud (try it) does sound like chicken.

2. HERPES

Herpes was first identified by ancient Greek scholars. Hippocrates himself described the nature of the virus, although at that time the term herpes could be used to describe a number of skin complaints. Because herpes spreads through skin lesions, the Greeks named herpes from the word meaning "to creep," describing how the virus transmits from one person to another.

3. TYPHUS & TYPHOID

Typhus is a disease spread by lice, which causes high fever, headache, and a dark red rash. The name comes from the Greek typhos, meaning "smoke or fog," thought to be because the high temperatures of the disease causes delirium in which the patient feels disoriented and confused, as if in a fog. The unrelated disease typhoid, which means "typhus-like," is so-called because it presents in a very similar way to typhus.

4. SYPHILIS

Hieronymus Fracastorius (Girolamo Fracastoro) shows the shepherd Syphilus and the hunter Ilceus being warned against yielding to temptation with the danger of infection with syphilis,  by Jan Sadeler, Wellcome Images via Wikimedia // CC BY 4.0

Syphilis was named from a poem, Syphilis sive morbus Gallicus” (“Syphilis or the French Disease”), by Italian Dr. Girolamo Fracastoro in 1530, in which a shepherd called Syphilus catches the disease. Due to the virulence and prevalence of the disease in the 17th and 18th centuries it was colloquially named after enemies—thus in England it was known as the French disease, the French called it the Neapolitan disease or the disease of Naples, the Russians called it the Polish disease, the Poles called it the Turkish disease, etc. 

5. MALARIA

The name malaria comes from the Italian for bad air (mal aria). Before the development of germ theory in the late 19th century, many thought that the disease came from breathing in the putrid fumes from swamps. It was not until 1880 that French army surgeon Charles Louis Alphonse Laveran noted the malaria parasites present in a sufferer’s blood, for which he was awarded the Nobel Prize.

6. CANCER

Edwin Smith Papyrus. Image viaJeff Dahl, via Wikimedia Commons // Public Domain

Cancer as a group of diseases has existed side by side with humans since the beginning of recorded history. The first known written description (although at the time they did not call it cancer) is from an ancient Egyptian papyrus from 3000 BCE, which describes treating breast cancer. Hippocrates, the Greek father of medicine, was the first to coin the name cancer, after the Greek word karkinos for crabs. No one is quite sure of his reasoning, but one of the suggestions is because of the way the tumors spread and surround healthy tissue in a crab-like fashion.

7. THE FLU

A family threatened by influenza is prepared for a large-scale bleeding. Wellcome Images //CC BY 4.0 

The origin of the name influenza reveals old ideas about how and why illnesses were caught and spread. The term derives from the Italian word for influence, reflecting the belief that catching the disease was caused (or influenced) by the positions of the planets in astrology. Initially, "influence" related purely to astrology, meaning an ethereal liquid that supposedly flowed down from the stars, affecting the health of humans when they were in certain "bad" positions. In Italian, "influenza" came to mean the outbreak of a disease due to the positions of the stars. It was this aspect of the meaning that was adopted to represent the illness we now understand as influenza, which we shortened in the English language to flu.

8. ASTHMA

The concept of asthma has been known throughout history, and references have been found in ancient Egyptian and ancient Greek texts. The word derives from the Greek aazein, meaning to pant or exhale with an open mouth, and its first recorded use is in Homer’s Iliad (although not in the context of the disease). It was not properly recognized as an inflammatory disease until the 1960s, since prior to this it had frequently been dismissed as a psychosomatic illness.

9. RABIES

Rabies is an extremely serious illness which is almost always fatal once symptoms of the disease manifest. It is spread by the bite from an infected animal, most commonly dogs, but fortunately these days it can be prevented by administering a vaccination immediately after being bitten. Because of the way the disease causes hyperactivity, hydrophobia, and frothing of the mouth, it was named after the Latin term rabere, which means "to rave."