An eponym is a word named after a person, such as sandwich, boycott, and the unit volt.

The longer version

Proper names turn into common nouns once users stop thinking about the person. The snack is credited to a nobleman who wanted meat between slices of bread; boycott comes from the name of a land agent whose tenants refused to deal with him; volt honours an Italian physicist who worked on electrical cells.

Such words usually lose their capital letter as they become ordinary, which is the clearest sign that the name has been absorbed. Science favours the device, giving units and effects a discoverer's surname, though language often fights back in favour of plain description. A few eponyms are backwards, where a place or object gave the person the name instead.

Where this entry sits

This category gathers small surprises about the English language, from odd spelling rules to words that quietly hide their own history. Expect palindromes, punctuation oddities, borrowed terms, and the strange ways writing systems record spoken speech. The full list sits on the Words and Language page, where every entry is listed in order.