Noun | 1. | isothiocyanate - a family of compounds derived from horseradish and radishes and onions and mustards; source of the hotness of those plants and preparations table mustard, mustard - pungent powder or paste prepared from ground mustard seeds horseradish, horseradish root - the root of the horseradish plant; it is grated or ground and used for seasoning mustard - any of several cruciferous plants of the genus Brassica Raphanus sativus, radish - Eurasian plant widely cultivated for its edible pungent root usually eaten raw Allium cepa, onion plant, onion - bulbous plant having hollow leaves cultivated worldwide for its rounded edible bulb chemical irritant - a substance producing irritation |