> explain why "Gaussian" and why "splat".

Happily. Gaussian splats are a technique for 3D images, related to point clouds. They do the same job (take a 3D capture of reality and generate pictures later from any point of view "close enough" to the original).

The key idea is that instead of a bunch of points, it stores a bunch of semi-transparent blobs - or "splats". The transparency increases quickly with distance, following a normal distribution- also known as the "Gaussian distribution."

Hence, "Gaussian splats".