An eponym is the name of a person or thing, whether real or fictitious, after which a particular place, tribe, era, discovery, or other item is named or thought to be named.^{[citation needed]} One who is referred to as eponymous is someone who gives his or her name to something, e.g., Julian, the eponymous owner of the famous restaurant Julian's Castle. Another term for eponym is namegiver.

In contemporary English, the term self-titled is often used to mean eponymous in the case of a work with the same name as the person or persons who created it.^{[citation needed]} An etiological myth can be a "reverse eponym" in the sense that a legendary character is invented in order to explain a term. This is one example of folk etymology.^{[citation needed]}

In different cultures, time periods have often been named after the person who ruled during that period.

By person's name

By category

For examples, see the comparison table below.