noun
Mercurialis leiocarpa; a species of mercury plant used for indigo dye
A plant in the spurge family whose leaves yield a blue dye. The name is sometimes read やまい in older texts, but やまあい is standard.
ヤマアイはかつて藍染めに使われた植物です。
Yamaai is a plant that was once used for indigo dyeing.
Kanji spelling; rarely used in practice. The reading やまい is obsolete.
藍 refers to indigo in general or the indigo plant (Persicaria tinctoria), while ヤマアイ is a specific mercury species also used for blue dye.
Compound of 山 (yama, 'mountain') and 藍 (ai, 'indigo'), referring to a mountain plant used for indigo dye. The exact historical derivation is uncertain.