eyebright

noun

1. (countable, uncountable)Any of the flowering plants of the genus Euphrasia, originally as used to treat eye infections.

   “Paracelsus had been recommending the plant eyebright for bad eyes in the sixteenth century; it was still in widespread use in the eighteenth.”

   “He looks for eyebright, a tiny flowering herb he has seen before, and which he knows would make a good eye-wash: not to be found.”