What's the difference between a Caisson and a Pier?

In the video in the Structural Issues module, the inspector stated that the columns on the front porch should have been built on caissons. I research every term I don’t know or understand, and it looks like a concrete pier.

A concrete pier typically consists of a round or square concrete pillar supported at the bottom by a footing piece which serves to spread the load carried by the pier. The pier is placed or cast with the footing below the frost line and its top end above the ground surface


Difference Between Piles, Piers and Caissons - Civil Engineering.


Thanks! Lol