Definition of November moth in US English:

November moth

noun

  • Either of two European geometrid moths of the genus Epirrita which fly in November, E. dilutata, a light brown to grey moth with darker forewings, and the paler E. christyi; (formerly also) †the feathered thorn, Colotois pennaria, a light reddish-brown geometrid moth (obsolete).

Origin

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