[ryukoposting]

In the industry, we called "normal" barcodes "2D," and stuff like QR and Aztec were called "3D" barcodes. Think of the "Z" axis as the coloration of a given point.

In all barcodes I'm aware of, that Z axis only has one bit of resolution (i.e. black or white, 1 or 0). If you had an encoding with more colors, you'd be increasing the resolution of that axis, but you wouldn't be adding a new axis per se.

Honestly, I also think 1D/2D would make more sense. But, 2D/3D is the nomenclature I saw being used among industry professionals on both the marketing and engineering sides.