Named after the Seneca, one of the Native American nations of New York.
The official version is that the avenue was named for the Seneca, one of the six nations of the Iroquois Confederacy, a New York people whose name for themselves was Onandowaga, ‘people of the hill’. The name Seneca itself came, via Mohegan and Dutch, from a name first used for the Oneida. Seneca was also the name of a Roman philosopher, statesman and dramatist.