horseradish Syllabification: (horse·rad·ish)Pronunciation: /ˈhôrsˌradiSH/Translate horseradish | into German | into Italian | into Spanish Definition of horseradish noun a European plant of the cabbage family, with long docklike leaves, grown for its pungent root. Armoracia rusticana, family Brassicaceae the root of the horseradish plant, which is scraped or grated as a condiment and often made into a sauce. horseradish in other Oxford dictionaries Definition of horseradish in the British & World English dictionary