The authors agree that the surname was formed from a medieval Germanic personal name, composed of elements linked to the lexical field of old age and the spear.

It is considered that the surname belongs to a set of forms of clear Germanic ancestry, derived from the name Hadalgher (from had(u), "battle", and gher, "spear"), introduced to Italy with the Lombards and adapted to Medieval Latin. From this name were formed variants such as Aldegheri, Aldigheri and Aldigiero, by phonetic evolution and by the addition of suffixes.

The main areas recorded are the province of Verona (Verona, San Martino Buon Albergo, Colognola ai Colli, Tregnago, Illasi). The surname belongs to the same onomastic group as other related forms such as Aldebrandi, Aldobrandi, Aldovrandi, Altebrandi, Altebrando, Altobrando (derived from Aldobrandus, "old sword"); Alderici, Alderighi, Aldrigo (from Aldericus, "old ruler"); and Aldovini, Aldovino, Alduini, Alduina, Alduno (from Aldovinus, an adaptation of Hardwin, "strong friend").

V. Blunda, for the Sicilian variant, derives it from the Germanic compound Alda Gaira, meaning "old spear" or "spear of the elder", formed from alda ("old, aged, wise through age") and gaira ("spear"). He notes that in Lombard society, the spear inherited from the father or grandfather was a symbol of family continuity and of the transmission of the right to bear arms. He adds that the form -gheri, with a fricative velar, is typical of the phonetics of northern Italy.