What is the difference between a rim joist and an end joist?

A rim joist, also known as a band joist, is the joist that runs along the perimeter of a floor system, providing support for the ends of the floor joists and acting as a barrier to airflow and insulation. In contrast, an end joist is a specific joist located at the end of a span, connecting two adjacent joists or providing additional support at the end of a row. While both serve structural roles, the rim joist is integral to the overall framing of the building, whereas the end joist is focused on connecting and supporting individual joists.