理学|りがくrigaku[1]atamadaka (head-high)

1. noun(physical) science; natural science
2. nounphysics
3. nounphilosophy
4. nounneo-Confucianism

• Synonym自然科学しぜんかがくWrittenWritten term: an umbrella for physics, chemistry, biology and earth science. 「理学」 is mostly used in faculty names like 「理学部」.
• Related自然哲学しぜんてつがくFormalFormal: the ancient Greek philosophical study of nature, forerunner of today's natural sciences. 「理学」 covers the modern basic natural sciences.
• Related窮理学きゅうりがくFormalFormal and archaic: the late-Edo term for Western physics, the study of matter and the laws of its motion. Modern usage says 「理学」.
• RelatedナチュラルサイエンスNeutralNeutral katakana loanword for natural science. In everyday speech 「自然科学」 is the usual choice.
• Related格物学FormalFormal and archaic: a Meiji-era name for physics, from the idea of investigating things to gain knowledge. Today say 「理学」 or 「物理学」.

Use 「理学」 for natural science in faculty names like 「理学部」 or 「理学博士」. For the sciences as a whole, especially in writing, say 「自然科学」. 「格物学」 and 「窮理学」 are old names for physics, 「自然哲学」 for Greek natural philosophy; the katakana loanword is not for daily use.

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

1. 物理学ぶつりがく、生物学せいぶつがく、化学かがく、地学ちがくなどの自然科学しぜんかがくの基礎きそとなる学問がくもんの総称そうしょう。
2. 物理学ぶつりがくの略称りゃくしょう。
3. 性せい理学りがくの略称りゃくしょう。