(chemistry) any salt or ester of the hypothetical isothiocyanic acid; or the -NCS radical or the NCS⁻¹ anion; isomeric with thiocyanate

plural of isothiocyanate

(organic chemistry) A mildly toxic pungent compound, C₃H₅NCS, obtained from the seeds of black mustard (Brassica nigra) or prepared synthetically, used as an animal repellent, etc.