horehound

 
Pronunciation: /ˈhɔːhaʊnd/
(also hoarhound)

noun

  • a strong-smelling hairy plant of the mint family, with a tradition of use in medicine.
    • Two species in the family Labiatae: white horehound (Marrubium vulgare) and black horehound (Ballota nigra), a Eurasian plant which was formerly said to cure the bite of a mad dog
  • [mass noun] the bitter aromatic juice of white horehound, used especially in the treatment of coughs and colds.

Origin:

Old English hāre hūne, from hār (see hoar) + hūne, the name of the white horehound, also applied to related plants