Definition of devil's milk in US English:

devil's milk

noun

rare, historical
  • Either of two common spurges, petty spurge, Euphorbia peplus, and sun spurge, E. helioscopia; (also) the white latex contained in these plants, which can irritate the skin.

Origin

Late 16th century; earliest use found in Henry Lyte (1529–1607), botanist and antiquary. From the genitive of devil + milk, after Dutch duivelsmelk and German Teufelsmilch.

Pronunciation

devil's milk

/ˌdɛvlz ˈmɪlk/