How to say "core" in Japanese

• コアCommon
  nounThe borrowed word for the central part of something, common in technical, scientific and business contexts; it keeps the flavor of the English original.
• 核心かくしんCommon
  nounThe heart of the matter: the essential point or crux of a problem, argument or issue. This is the usual choice when 'core' refers to the most important part of something abstract.
  これがその問題もんだいの核心かくしんである。↗

  This is the core of the problem.
• 主体しゅたいJLPT N1approx.Common
  nounThe main constituent or nucleus of a group or activity — the element the rest is built around, often with the nuance of the acting, leading part rather than the innermost center.
• 中核ちゅうかくCommon
  nounThe nucleus or central core of an organization, group or system — the part that holds the whole together. Suited to institutional and structural 'cores' rather than the essential point of a problem.
• 基軸きじくCommon
  nounThe foundation or basis on which a policy or system rests — the axis everything turns on. Use it when 'core' means the supporting basis or criterion rather than a part inside the whole.

Choose 「コア」 for the straight loanword; 核心 for the crux of a matter; 中核 for the nucleus of an organization or system; 主体 for the main constituent; 基軸 for the underlying foundation or criterion.

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

• コアcore
• 核心かくしんcore
• 主体しゅたいmain constituent
• 中核ちゅうかくkernel
• 基軸きじくbasis
• 中心ちゅうしんcenter
• 根幹こんかんfoundation
• 眼目がんもくmain point
• 中子なかごcore
• 中心核ちゅうしんかくcore (of planets, stars, galaxies, etc.)
• 核心的かくしんてきcrucial
• 磁心じしん(magnetic) core
• 地核ちかく(Earth's) core
• 心しんbottom of one's heart
• 核かくcore (of an organization, team, etc.)
• 芯しんcore
• 命いのちmost important thing
• 骨ほねoutline
• 本丸ほんまるcore