elementary geometry
Refers to the branch of geometry taught at the introductory level, typically covering points, lines, angles, and basic shapes.
In elementary geometry, we learn the conditions for triangle congruence.
幾何学 is the general term for geometry, while 初等幾何学 specifically refers to the elementary or introductory level.
Compound of 初等 (elementary) and 幾何学 (geometry). 幾何学 is a Meiji-era coinage from Chinese 幾何 (how much, geometry) and 学 (study).