How to say "primary" in Japanese

• 初等しょとうCommon
  prenominal modifierCovers 'primary' in the educational sense — the first stage of schooling, as in primary or elementary education. Think of it as the adjective for primary-level education, not for 'primary' meaning chief or most important.
• 一級いっきゅうCommon
  na-adjective, nounReally 'first-class' or 'grade one': a top rank in a numbered system, as with graded licences or quality classes. Its 'primary' reading belongs to that first-in-series sense, so it is seldom the word you want.
• 主たるしゅたるCommon
  pre-noun adjectivalCovers 'primary' in the sense of main, principal or chief: the primary reason, objective or concern among several. Reach for it whenever 'primary' could be swapped for 'main' or 'principal'.
  私の主しゅたる関心事かんしんじはあなたの身みの安全あんぜんなのです。↗

  My primary concern is your safety.
• 原発げんぱつCommon
  no-adjective, suru verbMedical 'primary': a disorder or syndrome that is primary — the original condition, not one secondary to another, as in primary immunodeficiency. The same string also abbreviates 'nuclear power plant', so context decides the reading.
• 予選よせんCommon
  noun, suru verb, transitive verbA noun for a preliminary stage: the 'primary' of a preliminary election narrowing the candidates, and generally a qualifying round or screening before the main event — not the adjective 'primary'.

Use 初等 for primary schooling, 「主たる」 for the main/principal sense, 原発 for a primary medical condition, 予選 for a preliminary election or round, and 一級 only for first-class, graded ranking.

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

• 初等しょとうelementary
• 一級いっきゅうone grade
• 主たるしゅたるmain
• 原げんoriginal
• プライマリprimary
• 原発性げんぱつせいprimary
• 初列しょれつprimary (feathers)
• 一次性いちじせいprimary
• 予備選挙よびせんきょpreliminary election
• 第一次だいいちじthe first ...
• 第一義的だいいちぎてきfundamental
• 予備選よびせんpreliminary election
• 原発げんぱつprimary (e.g. primary immunodeficiency syndrome)
• 予選よせんpreliminary selection
• 一次いちじprimary (sources, industry, etc.)
• 一義的いちぎてきprincipal