milk thistle

milk thistle (plural milk thistles)

1. Any of the thistles in the genus Silybum, especially Silybum marianum.
2. Lactuca serriola, prickly lettuce
3. Various plants of genus Sonchus (sow thistles) with milky sap:
   1. Sonchus asper rough milk thistle
   2. Sonchus arvensis field milk thistle
   3. Sonchus oleraceus (common sow thistle)
   4. Sonchus wilmsii

• (Silybum marianum): blessed milk thistle, holy thistle, variegated thistle