1. Tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads; naturalized in California and South America
   "holy thistle is often used in herbal medicine for liver problems";
   - milk thistle, lady's thistle, Our Lady's mild thistle, blessed thistle, Silybum marianum

Derived forms: holy thistles

Type of: herb, herbaceous plant

Part of: genus Silybum, Silybum

Encyclopedia: Holy thistle