sustainable Syllabification: (sus·tain·a·ble)Pronunciation: /səˈstānəbəl/Translate sustainable | into French | into German | into Italian | into Spanish Definition of sustainable adjective 1able to be maintained at a certain rate or level:sustainable fusion reactions conserving an ecological balance by avoiding depletion of natural resources:our fundamental commitment to sustainable development 2able to be upheld or defended:sustainable definitions of good educational practiceDerivatives sustainabilityPronunciation: /səˌstānəˈbilitē/ noun sustainablyPronunciation: /-blē/ adverb sustainable in other Oxford dictionaries Definition of sustainable in the British & World English dictionary