What is a classic car ornament called?

Virtually all early car makers had an ornament , logo or icon displayed on the car, often called by a unique descriptive name and more recognizable than the car's name.

Before the 1940's radiator caps usually featured an auto maker's ornament.

As the radiator was moved under a hood. the ornament became a "hood ornament", placed on the hood near the grille. Also a logo unique to that make of car was placed on the outer body of the car or on the steering wheel as a horn button.