noun-modifying (irregular)
triennial; three-year (plan, period, etc.)
Used attributively to describe a plan, project, or period spanning three years. Common in government, business, and institutional contexts.
The city announced a three-year plan.
There has been great progress during these three years.
Commonly used in official documents and plans; the small katakana カ is a standard way to write the counter.
The small katakana ヶ is a variant of カ and is also widely seen.
Hiragana か is sometimes used, but less common in formal writing.
Uses the kanji 箇, which is the formal character for the counter; rarely seen in modern texts.
Variant with small katakana ヵ; less common than カ or ヶ.
Full-size katakana ケ is occasionally used but nonstandard.
Using Arabic numeral 3 instead of kanji 三; common in charts and tables.
Arabic numeral with ヶ variant.
Arabic numeral with hiragana か.
Arabic numeral with kanji 箇.
Arabic numeral with ヵ variant.
Arabic numeral with full-size ケ.
Compound of 三 (three) + カ (counter for years, derived from 箇) + 年 (year). The counter カ/ヶ/か is a simplification of the kanji 箇.