What is the term for the forerunner of today's hearse?

The term for the forerunner of today's hearse is the bier. A bier is a stand or frame used to support a coffin during a funeral service or while it is being moved. Historically, biers were often used to carry the deceased, much like how hearses are structured today to transport caskets. The function of the bier in the past aligns closely with the purpose of a hearse in modern times, which is designed specifically for the transportation of the deceased during funeral services.

Other choices, while related to funeral practices, do not directly serve as the basis for today's hearses. A casket refers specifically to the container for the deceased, while a coach typically refers to a vehicle, which can indeed describe hearses, but doesn't specifically denote the earlier model used for transporting the deceased. A chariot, though used in ancient times for a variety of purposes, is not directly related to funeral transportation in the same context. Therefore, bier is the term that most accurately identifies the historical antecedent of contemporary hearses.