An ongoing debate in Arabic morphology concerns the nature of the smallest unit governing lexical organization and representation in this language. A standard model maintains that Arabic words are typically analyzable into a three-consonantal root morpheme carrying the core meaning of words and a prosodic template responsible mostly for grammatical information. This view has been largely supported by research in both theoretical linguistics and psycholinguistics. An alternative theory holds that the meaning of words in Arabic is, rather, encoded in the ‘etymon’ comprising two unordered consonants of the root only. Results from a recent priming experiment have shown that the etymon induces strong morphological priming effects, supporting its morphological/lexical status. In this paper we present data from a patient with deep dyslexia questioning the role of the etymon as a psychologically real representational unit in Arabic and arguing, instead, for the central role of the root in both morphological and lexical representation in this language.