Which fictional people did J.R.R. Tolkien call the Rohirrim?

The Rohirrim are the horse-lords of Rohan in J.R.R. Tolkien’s legendarium.

Rohan is a kingdom of Men whose culture, military strength, and identity are closely tied to horses. The people are called the Rohirrim, while a single male inhabitant is a Rohir. Their language and names draw strongly on Old English, reflecting Tolkien’s scholarly interests and his design of Rohan as a horse-centered society.

The Rohirrim play a major role in The Lord of the Rings, especially when King Théoden and his riders aid Gondor. They are not Elves or a separate supernatural species; they are Men of Middle-earth with a distinctive kingdom, history, and alliance with Gondor.