"connoisseur," 1778 (in the plural cognoscenti), an Italian word in English, re-Latinized in Italian from earlier conoscente "connoisseur," literally "knowing man," from Latin cognoscentum (nominative cognoscens), present participle of cognoscere "to get to know, recognize," from assimilated form of com "together" (see co-) + gnoscere "to know," from PIE root *gno- "to know."
cognizance
cognizant
cognize
cognomen
cognoscence
cognoscente
cognoscenti
cog-wheel
cohabit
cohabitate
cohabitation