Problematic of definition and terminology affecting primary teachers’mathematical knowledge for teaching geometry

Mathematics is often seen as universal across cultures. However, there exist differences in symbols, conventions, terminology, and definition used in different cultures. In some situations, the distinctions may be mathematically trivial and have no adverse effect on mathematics instructions. However, in other situations, there may be significant consequences on both mathematical understanding and instructions. This paper examines one such instances in the context of learning and teaching geometry in Indonesia, where the terminology, convention, and definition used caused hurdles in primary teachers’ knowledge and understanding of the geometry concepts they teach. Some suggestions to ameliorate these challenges are proposed.