G. Rohlfs considers that this surname is of Greek-Byzantine origin, present throughout Calabria and also in the region of Campania. He derives it from the Greek δάκτυλος ("finger"), which would have functioned as a descriptive nickname, and links it to the Byzantine presence in southern Italy and to the survival of the Greek lexicon in the onomastics of that zone.

P. Durante agrees in noting the Greek origin of the surname and likewise refers it to the term dàktylos ("finger"), without adding additional geographical or historical precisions.

A different perspective is offered by V. Blunda, who considers it a Sicilian surname of Germanic root. According to Blunda, it would derive from the personal name Dadilo, a diminutive form of the anthroponym Dado, whose root dad has a disputed sense. For this author, the popular association with the Greek daktylos ("finger") or with the fruit of the date constitutes a crossed etymology: although the formal similarity is notable, the surname would come from an earlier Germanic anthroponym, without relation to those words of Greek origin. Blunda notes that the surname is preserved especially in eastern Sicily and in zones of southern Italy with a continental Lombard imprint.

The sources present, therefore, two incompatible interpretations: one of Greek filiation, maintained by Rohlfs and Durante, which points to a nickname referring to the finger, and another of Germanic filiation, proposed by Blunda, which traces it back to a medieval personal name. Both positions remain open without any of the sources resolving them conclusively.