How to say "mechanics" in Japanese

• 力学りきがくCommon
  nounCovers mechanics as a branch of physics — the science of forces and motion — and also 'dynamics'. It is not used for machines or mechanisms; for those, メカ is the word.
  熱力ねつりょく学がくの背後はいごには、第だい１巻かんで学まなんだ力学りきがくの法則ほうそくにしたがう原子げんしや分子ぶんしの運動うんどうがあります。↗

  Behind thermodynamics lie the movements of atoms and molecules following the laws of motion learned in the first volume.
• メカCommon
  nounAn abbreviated term for machines, mechanisms and mechanical equipment; its 'mechanics' is this machinery sense, not the physics discipline — for that you need 力学.

力学 is the word for mechanics as a branch of physics (forces and motion; also 'dynamics'), while 「メカ」 is an abbreviation for machines, mechanisms and mechanical equipment, so it fits only the machinery sense of 'mechanics'.

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

• 力学りきがくmechanics
• メカmechanism
• メカニクスmechanics
• 機械学きかいがくmechanics