Marrubium vulgare

Horehound Hore"hound`, n. [OE. horehune, AS. h[=a]rhune; h[=a]r hoar, gray + hune horehound; cf. L. cunila a species of organum, Gr. ?, Skr. kn?y to smell.] (Bot.) 1. A plant of the genus {Marrubium} ({Marrubium vulgare}), which has a bitter taste, and is a weak tonic, used as a household remedy for colds, coughing, etc. [Written also {hoarhound}.] [1913 Webster]

2. A lozenge or tablet, usually sweetened, containing extract of horehound, used as a remedy for a cough or a sore throat. [PJC]

{Fetid horehound}, or {Black horehound}, a disagreeable plant resembling horehound ({Ballota nigra}).

{Water horehound}, a species of the genus {Lycopus}, resembling mint, but not aromatic. [1913 Webster]