Abstract

Almost all researchers dealing with derivation of words in Arabic refer to ibn Fares’s work in etymologizing multi-letter words. Considering this issue, ibnu Fares stated the following: "We think that most multi-lettered words are contaminated". However, the rest of those words, which are a minority according to him, are considered either affixated words derived from trilaterals by adding one or more letters, three- or four-lettered words originally spoken the way they are since their origin.  
This research considers ibn fares’s approach as a theory and attempts to confirm or refute it through investigating the multi-lettered words in his dictionary "Maqayis AL Lugati". The research also tries to show the imperfection of ibn fares’s judgment, but at the same time it gives him the credit for his ideas, had they not been ignored by the former linguists, they would have opened new horizons in the field of derivation and etymology in Arabic.