milfoil

The word 'milfoil' is a direct borrowing from the Anglo-Norman French milfoil, itself derived from the Latin millefolium, a compound of mille ("thousand") and folium ("leaf"). This name is a vivid botanical descriptor, referring literally to the plant's "thousand leaves," which is a visual metaphor for its characteristic feathery, finely-divided foliage. The Latin term passed into Middle English, retaining its literal meaning and serving as the common name for the yarrow plant. The logic of the name perfectly captures the plant's most distinctive morphological feature, translating an ancient descriptive phrase into a precise modern identifier.

Structure: mil (thousand) + foil (leaf) - mil: From Latin mille, meaning "thousand". In this compound, it functions as an intensifier denoting "many". - foil: From Old French foille, from Latin folium, meaning "leaf". It functions as the core noun element.