ablaut Syllabification: (ab·laut)Pronunciation: /ˈabˌlout/Definition of ablaut noun a change of vowel in related words or forms, e.g., in Germanic strong verbs (e.g., in sing, sang, sung). Origin: mid 19th century: from German, from ab 'off' + Laut 'sound'ablaut in other Oxford dictionaries Definition of ablaut in the British & World English dictionary