What is it with the nomenclature of AFV-using units? For instance, the Brazilian Army's battalion-level types are:
>Armored infantry, 100% tracked APC (M113)
>Armored cavalry, 50% tank (Leopard 1 or M60)/50% tracked APC (M113)
>Tank (part of the cavalry), 100% tank (Leopard 1)
>Mechanized cavalry, 50% armored car (Cascavel)/50% wheeled APC (Urutu, in the future Guarani)
>Mechanized infantry, 100% wheeled APC (Guarani)

A wealthier military would replace some of those APCs with IFVs.
Aside from the tank regiments the names aren't quite descriptive. All of them are mechanized in the sense that machines replace human labor in several tasks, more so than in motorized infantry. And all of their vehicles have armored protection, the tanks just have more of it. The clearer distinction is that armored = tracked vehicles and mechanized = wheeled vehicles. Even "tracked cavalry regiment" and "wheeled cavalry regiment" would be clearer. Perhaps those with tanks and/or IFVs could be called "heavy", APCs "medium" and trucks "light" (already the case sometimes).