eu·caine \yüˈkān, ˈ ̷ ̷ˌ ̷ ̷\noun (-s) Etymology: International Scientific Vocabulary eu- + -caine; originally formed as German eucain (now eukain) : a local anesthetic C15N21NO2 derived from piperidine and usually administered as the white crystalline hydrochloride — called also beta-eucaine