E. Rossoni considers that this surname would derive from the medieval name Lenzo, documented in Tuscany with examples such as Lenzo di Corsinetto, procurator of the village of Boccheggiano, in the Grosseto area, in the year 1400. According to Rossoni, the surname has a main core, very widespread, between the Bologna area and the whole of Tuscany, with areas of probably native origin also in Trentino, in Lombardy and in Rome.

F. De Laurentiis proposes, by contrast, that the base of the surname would be a nickname derived from the noun lenza, a term designating the fine line of silk, horsehair or nylon to which the hook is attached and which is used by anglers, which would suggest an origin in a trade or a personal trait connected with fishing.