The word is parsed as a compound with the intensive prefix ζα-. Although ζάγκλον is a Sicilian word and ζα- is an Aeolic form of διά, and Aeolic forms are certainly not at home in Sicily, the explanation is rather simple and Greek scholars did not pay attention to dialectal facts (it was enough that ζα- was attested in Homer to have the right to assume it in Greek gererally speaking). This is a descriptive etymology referring to the form of the tool. It implies only one formal manipulation, a syncope of [u].