Etymology   The etymology section was completely wrong The Hebrew consonant Tsade results from the merging of at least two protoSemitic consonants They are still distinct in Classical Arabic as ad and ad It is easy to see that chamets corresponds to the Arabic root m because the Aramaic version which appears in the Aramaic parts of the Hagada is amia with Ayin and almost all Arabic ads map to Ayin in Aramaic In Hebrew the root means both sour and leavened cf chamuts sour chomets vinegar chumtza acid In Arabic it is used mostly to denote sour or acidic In any event chamets is not related to hummus or Homs Hummus is chimtza in Modern Hebrew and in one case chometz in the Bible might be hummus rather than vinegar but the root is historically different and only accidentally did they assume the same phonetic shape