Meaning

noun colorless pungent crystalline compound derived from capsicum; source of the hotness of hot peppers of the genus Capsicum such as chili and cayenne and jalapeno

originArbitrary alteration of earlier capsicine, capsicin (“material extracted from cayenne pepper”), presumably to prevent confusion, from German Capsicin, from New Latin capsicum + German -in. Name introduced by John Clough Thresh (1850–1932) in “Capsaicin, the Active Principle of Capsicum Fruits”.

Etymology from Wiktionary, CC BY-SA 3.0