In Europe, we only regard Group 4 and Group 5 as 'Synthetic'
Group 3 is labelled as Semi-Synthetic
Groups 1 & 2 are labelled as Mineral.
This is incorrect. In most of Europe (as in most of the world), the term "fully synthetic" is applied to any oil containing 100% Group III, IV or selected V base oils. The term "semi-synthetic" does not refer to, and never has referred to, a group III base oil. The term "semi-synthetic" refers to a blend of groups I/II with group III/IV/V.
The only exception in Europe is Germany, where group III has its own reference, "HC-Synthese". Still "synthetic", but hydrocracked synthetic.
And once again I must point out that group V is not a synthetic category - it is a broad category that includes some synthetics (ester for example) and many non-synthetics (naphthenics, MVIs and so on).