milk thistle meaning and definition

MILK THISTLE noun

Definition of milk thistle (noun)

1. any of several Old World coarse prickly-leaved shrubs and subshrubs having milky juice and yellow flowers; widely naturalized; often noxious weeds in cultivated soil
   • synonyms: sow thistle
2. tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads; naturalized in California and South America
   • synonyms: blessed thistle, holy thistle, lady's thistle, Our Lady's mild thistle, Silybum marianum