The Collaborative International Dictionary
Horse-radish
Horse-radish \Horse"-rad`ish\, n. (Bot.)
A plant of the genus Nasturtium ( Nasturtium Armoracia),
allied to scurvy grass, having a root of a pungent taste,
much used, when grated, as a condiment and in medicine.
--Gray.
Horse-radish tree. (Bot.) See Moringa.
Wiktionary
horse-radish
n. (alternative spelling of horseradish English)