Definition of oak beauty in English:

oak beauty

noun

(also oak beauty moth)
  • Any of several moths associated with oaks; (now) specifically the Eurasian geometrid moth Biston strataria, with brown and white speckled wings, the larva of which feeds on woodland trees including oak, hazel, and elm.

Origin

Late 18th century; earliest use found in Moses Harris (1730–c1788), entomologist and artist.