The tag usage guidance for geometry goes
For questions about geometric shapes, congruences, similarities, transformations, as well as the properties of classes of figures, points, lines, and angles.
To me this sounds essentially like 'geometry for highschool/grade school/pre-university/primary school/secondary school'. Of course you click and see the full tag info and see that geometry can also be tagged for university 'geometry' that maths majors (and some physics majors) take.
- 3.1. Actually, the full tag info I find is kind of weird. Everything before 'Sub-fields of Contemporary Geometry' suggests pre-university geometry while everything afterwards suggest university 'geometry'.
I also think it's kinda redundant to tag geometry with every single differential-geometry or complex-geometry, but eh I guess it's like tagging probability-theory with every martingale or (stochastic-calculus or stochastic-analysis) with every stochastic-differential-equations