Wiktionary
n. (context organic compound English) A pungent compound, C3H5NCS, obtained from the seeds of black mustard, (taxlink Brassica nigra species noshow=1) or prepared synthetically; sometimes known as mustard oil; it is mildly toxic and is used as an animal repellent, etc.
Wikipedia
Allyl isothiocyanate (AITC) is the organosulfur compound with the formula CHCHCHNCS. This colorless oil is responsible for the pungent taste of mustard, radish, horseradish, and wasabi. This pungency and the lachrymatory effect of AITC is mediated through the TRPA1 and TRPV1 ion channels. It is slightly soluble in water, but more soluble in most organic solvents.
Usage examples of "allyl isothiocyanate".
It is distilled from the seeds that have been deprived of most of the fixed oil and macerated in water for several hours, and contains from go to 99 per cent of the active principle, Allyl isothiocyanate, which is used as a counter irritant.