Noun has 2 senses

• milk thistle(n = noun.plant) sow thistle - 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;




• milk thistle(n = noun.plant) blessed thistle, holy thistle, lady's thistle, our lady's mild thistle, silybum marianum - tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads; naturalized in California and South America;