gluco- Look up gluco- at Dictionary.com
before vowels, gluc-, word-forming element used since c.1880s, a later form of glyco-, from Greek glykys "sweet," figuratively "delightful; dear; simple, silly," from *glku-, dissimilated in Greek from PIE root *dlk-u- "sweet" (source also of Latin dulcis). Now usually with reference to glucose.