We can divide ambiguity in etymological structures of the Arabic language in two types: 1-Ambiguities that might arise, but have been prevented by taking some tact. 2- Structures that are potentially produced ambiguity. Early scholars have named only the first case as ambiguity, because according to them, basically, understanding the meaning is done according to the context and this eliminates ambiguity. But in the new study, the second type is based on this research, is viewed as a serious ambiguity. These researches have often paid some of these aspects sporadically, but in this study, we have tried to provide a new theoretical framework and complete with mention two categories of the concepts of homonymy and polysemy. Also, in a comparative dimension, the study translations of the Holy Quran shows that this kind of ambiguity is very clear in translation for this purpose, after studying of etymological structures in the Arabic language, we determined those funds that are creating ambiguity and then, we analyzed translations of the Quran with computer softwares and we extracted samples. These funds are in a variety of words, such as verbs, nouns and letters. Of these, homonymy is eleven (11) and polysemy is eight (8). Accordingly, on the one hand, the translator must be aware of these structures compeletly and on the other hand, the translator must have the necessary vigilance to find evidence about linguistic and non-linguistic signs which indicate the intended meaning to give priority to a semantic aspect on the other side.