Namesake

Etymology

Believed to come from the phrase "for the name’s sake" — someone named for another’s sake. "Sake" traces to Old English "sacu" (a cause, suit, or matter at law), the same root buried in "for goodness’ sake."

noun · /NAYM-sayk/
A person or thing named after another.
What it names
A tidy word for the link between two things that share a name — a child named for a grandparent, a town for its founder.
Example
The bridge is the namesake of the engineer who first designed it.
Related idea
A namesake can point either way — the one named after, or the one they were named for; an eponym, by contrast, is specifically the source name, like the Mentor who gave us "mentor."