1. (noun) tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads; naturalized in California and South America

• blessed thistle
• holy thistle
• lady's thistle
• milk thistle
• our lady's mild thistle

1. (noun) tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads; naturalized in California and South America

• genus silybum
• silybum

1. (noun) tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads; naturalized in California and South America

• herb
• herbaceous plant