IPA: /dʒiˈɒmɪtə/
KK: /dʒiˈɑːmɪtər/
A person who studies or works with the properties and relationships of shapes, sizes, and figures in mathematics.
The geometer presented his findings on the properties of triangles at the conference.
Geometer is formed from "geo-" (from Greek "geō", meaning earth) and "metron" (meaning measure). The word refers to someone who measures the earth, particularly in the context of geometry.
Think of 'earth' ('geo-') and 'measure' ('metron') to remember that a geometer is someone who measures the earth.