milk thistle

Short definition from Wiktionary

Noun

1. 1
   Any of the thistles in the genus Silybum, especially Silybum marianum.
2. 2
   Lactuca serriola, prickly lettuce
3. 3
   Various plants of genus Sonchus (sow thistles) with milky sap: Sonchus asper rough milk thistle
4. 4
   Various plants of genus Sonchus (sow thistles) with milky sap: Sonchus arvensis field milk thistle
5. 5
   Various plants of genus Sonchus (sow thistles) with milky sap: Sonchus oleraceus (common sow thistle)
6. 6
   Various plants of genus Sonchus (sow thistles) with milky sap: Sonchus wilmsii