In any language, words both evolve and are created out of thin air. It is not unusual for a certain person or place to become associated with a trend, item, or invention and for that name to then become a common word in a language. These words are called 'eponyms' and the English language has several examples. Here are four:
Why not start with the most delicious of the eponyms? The Earl of Sandwich was an avid cardplayer (ahem, gambler), and he wouldn't leave the table for his meals. Instead, he would eat a piece of meat served between two slices of bread, an easy meal to hold in one's hands without a lot of extra silverware cluttering up the playing table. As the story goes, his fellow cardsharks came to so closely associate this meal with the Earl they started asking for a 'sandwich.'
A much less appetizing word than sandwich, 'gerrymander' is the process of apportioning legislative districts in such a way as to be politically beneficial to one party or another. The name results from legislation signed by Massachussetts Governor Elbridge Gerry that resulted in a salamander-shaped district in the Bay State. Combine Gerry + Salamander and you get both a compound word and an eponym!
It just sounds cool, right? Like the name just makes sense? The instrument's name didn't just appear out of thin air, though! It's named for its inventor, Adolphe Sax. We can just assume he was pretty hip.
Rudolf Diesel gives his name to this form of gasoline and engine. He invented the diesel engine in the early nineteenth century, and while he might not be widely remembered his name is widely used to this day.
If you dig further, you'll find plenty of other examples of eponyms in the English language. If you're interested in finding more, we recommend looking in the science sector, as inventions and discoveries lend themselves well to eponyms.