Fehling's solution Syllabification: (Feh·ling's so·lu·tion)Pronunciation: /ˈfāliNGz/ (also Fehling's reagent)Definition of Fehling's solution noun an alkaline solution of copper(II) sulfate and a tartrate, used in a laboratory test for sugars. Fehling's solution in other Oxford dictionaries Definition of Fehling's solution in the British & World English dictionary