Windfola

From Tolkien Gateway

Windfola was a grey horse of the Rohirrim.

Windfola was the horse that carried Éowyn (in the guise of Dernhelm) the long miles from Dunharrow to the Pelennor Fields, secretly accompanied by Meriadoc Brandybuck. Windfola was in the charge of the Rohirrim in the Battle of the Pelennor Fields, but at the onset of the Lord of the Nazgûl, the horse went mad with fear, threw his riders, and fled in panic. Left behind by their steed, Éowyn and Merry brought down the Witch-king of Angmar, but by then Windfola had left them far behind him on the battlefield.

Etymology

Windfola is Old English for "wind-foal".

Portrayal in adaptations

In The Lord of the Rings: The Return of the King, Éowyn rides a brown coated horse, which is presumably killed when it is crushed by the falling Oliphaunt. The horse used was called Dublin.