A European vetch of dry grassland, Vicia angustifolia, naturalized in the United States and now usually regarded as comprising two subspecies of the common vetch, V. sativa subsp. nigra and subsp. segetalis.
Origin
Late 19th century.
Definition of narrow-leaved vetch in US English:
narrow-leaved vetch
noun
A European vetch of dry grassland, Vicia angustifolia, naturalized in the United States and now usually regarded as comprising two subspecies of the common vetch, V. sativa subsp. nigra and subsp. segetalis.