Often PCB designers refer to the 2D images they see in the PCB design viewport as footprints (IPC -> Land Patterns).

Really they are 2D representations of physical devices (parts).
In reality they are more than footprints/land patterns (which are just the copper bonding sites).
The PCB design industry has many poorly named concepts.
I link to think of footprints as devices. They are placed on the PCB (or is it PWB?) and connected together normally using strips of copper and copper plated holes.  Now this might upset some.
DEX has an integrated model of a Device that displays itself in many forms:
  • One or more schematic symbols. These are logical images to allow you to logically define devices used and their required connectivity.
  • One and only one 2D footprint/land pattern displayed to make physical placement and electrical connections using Nets ( An acyclic graphical of tracks).
  • 3D Model. Yes all DEX footprints generate 3D models although the model can just be copper and silkscreen patterns for the top/bottom side and 3D holes.
  • Spice simulation model.
  • BOM part.
  • Zero or more PDFs (usually data sheets)
  • Zero or more Text Documents (usually data sheets)
  • Metadata such as manufacturer or user define parameters.

I have never felt comfortable calling what you see in the 2D PCB viewport as a footprint  It seems like I’m only telling half the story.