Namesake is a term used to characterize a person, place, thing, quality, action, state, or idea that has the same, or a similar, name to another.
In the United States, the term is often used for a person or thing actually named after, rather than merely sharing the name of another. For example, if a person, place, or thing is named after another person, place, or thing, then the name target is said to be the namesake of the name source. The earliest use reported in the Oxford English Dictionary was in 1635. Dictionaries suggest that the word probably comes from "name's sake", "for one's name('s) sake", for "name sake".
The term namesake was first recorded in 1635, referring to a place with the same name as another. Among other recordings, a 1646 usage was carried through in an 1806 publication, entitled A Critical Pronouncing Dictionary, and Expositor of the English Language. Modern-day usage has expanded to several uses for the term.
Using a namesake's name is a relatively common practice in naming children that has given rise to the large number of "Jr.", "III", and other name suffixes. Namesakes are often used in tribute to older, related persons, such as grandparents. Use of a namesake's name in a leadership position may indicate certain things, usually referring to certain traits of the namesake, such as in the use of papal regnal names.
Some commercial entities and products are named after their creators, such as the Trump Tower and Ford Motor Company. Items are also named after people associated with them, such as the teddy bear. This is especially the case with scientific discoveries and theories, such as Gibbs free energy. When the target name merely is derived from the source name without an additional "sake" connection, such usage more accurately may be called an eponym rather than a namesake.