How to say "geometry" in Japanese

• 幾何きかCommon
  nounAn abbreviation of 幾何学, meaning geometry as a branch of mathematics; it is a common word, and in mathematical discussion it is readily understood, though 幾何学 is the fuller form.
  明日あす幾何きかの試験しけんがあります。↗

  We're having an examination in geometry tomorrow.
• 幾何学きかがくCommon
  nounThe full name of geometry as a branch of mathematics; this is the word to use when naming the field of study, as in academic writing or mathematical discussion.
  ギリシャ人ぎりしゃじんたちは幾何学きかがくの理論的りろんてき原形げんけいを作つくった。↗

  The Greeks made theoretical models of geometry.

Both words mean geometry, the branch of mathematics; 幾何学 is the full name of the field, while 幾何 is its abbreviation, so for naming the subject 幾何学 is the more explicit choice.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 幾何きかgeometry
• 幾何学きかがくgeometry
• ジオメトリーgeometry