If you know even a small amount of any Romance language, many English words have relatively obvious etymological backgrounds. But the paths to their origins aren't always so clear when words are eponyms—coined from people's names—and scientists are very often the culprits in these cases. Here are some words you might not know were eponyms, and whose scientific namesakes have been hiding in plain sight.
The unit that measures electric potential is named after Count Alessandro Volta, an Italian physicist (pictured above) who invented the electrical battery, known as the voltaic pile, in 1800. The volt unit of measurement wasn’t approved by the International Electrical Congress until 1880, however, long after Volta had died. His memory also stuck around in yet another way, at least in Italy: Before the country switched over to the euro, he appeared on the 10,000-lira note.
Speaking of Volta: He was inspired (or perhaps egged on) in his research by his rival and contemporary physicist Luigi Galvani, who in the 1780s figured out that you can shock dead frogs and make their muscles twitch (he called his discovery "animal electricity"). A variety of words related to electricity were coined in Galvani's honor, but today the most commonly used in everyday speech is galvanize, meaning to excite someone or something into action.
Although the guillotine’s prototype was built by French doctor Antoine Louis and German engineer (and harpsichord maker) Tobias Schmidt, Dr. Joseph-Ignace Guillotin just, well, really liked it. The idea of a more humane killing machine so impressed the French Revolution-era anatomy professor that he stood before France’s National Assembly in 1789 to recommend it as a much less painful method of execution than the sword, axe, or breaking wheel. The Assembly laughed at him at first, but the lethal device—though first known as a Louison or Louisette (after Dr. Louis)—eventually became an eponym in Guillotin’s honor.
Scottish-born John Macadam was a well-respected chemist and politician in his adopted country of Australia, but he didn’t really have anything to do with the indigenous nut that bears his name.
Macadamias were originally called jindilli or gyndl by aboriginal people in Australia, among other names, but they weren’t named or even “discovered” by Europeans—ultimately via explorer Allan Cunningham—until 1828. German explorer Ludwig Leichhardt collected the first specimens in 1843, but it still took until 1858 for German-Australian botanist Ferdinand von Mueller to cook up a genus name for the plant. He called it Macadamia after his buddy John, esteemed scientist and secretary to the Philosophical Institute of Victoria.
Medieval Muslim astronomer and mathematician Muḥammad al-Khwārizmī has a few different words named after him, in a few different languages, but the one you’re most familiar with is probably algorithm. (The Latinized version of his surname was Algorismus.) He's also considered one of the fathers of algebra, after the title of his most famous book, Al-Kitāb al-mukhtaṣar fī ḥisāb al-jabr waʾl-muqābala (“The Compendious Book on Calculation by Completion and Balancing”)—al-jabr means "reunion of broken parts."
If you remember calling BBSes with your 2400-baud (or slower) dial-up modem in the ’90s, this word may ring a bell (or a carrier scream?). A baud measures symbols transmitted per second that are transmitted over a telecommunications link, and the term is an abbreviation of French engineer Émile Baudot’s name. He invented the Baudot code—a predecessor of ASCII—that was widely used in telegraphy in the late 19th and very early 20th century.
When French scholar Jean Nicot was appointed as ambassador to Portugal, he thought he’d impress the French court big time when he brought back some tobacco plants from a 1559 trip to Lisbon. (He’d originally picked them up from Portuguese humanist philosopher Damião de Góis, who’d hyped them as “miraculous.”) Back in France, Nicot made an ointment from the plant and successfully treated a patient’s tumor with it, after which he was convinced that tobacco would heal any ailment from gout to cancer. He next presented some tobacco leaves to French queen Catherine de Medici, touting it as a cure for her headaches, and the plant thereafter became popular among European nobility in the form of snuff. Two centuries later, Swedish naturalist Carolus Linnaeus named the genus of cultivated tobacco Nicotiana after Jean, and today, his name shows up in the addictive stimulant found in the nefarious nightshade as well.
Yes, he invented the phone, but Scottish-American engineer Alexander Graham Bell is responsible for a whole list of other cool stuff too, including an automated wheat-husker (which he built at age 12!), an audiometer to evaluate how well a person can hear, an early metal detector (in emergency response to the shooting of President Garfield), an improved version of Thomas Edison’s phonograph, and … the word bel, a unit that expresses the ratio of two values, usually of power or intensity. Taken from AGB’s last name, of course, bels are pretty big, and the word isn’t used often. As such, you may be more familiar with the word that describes a tenth of a bel: decibel.