The authors agree that this surname derives from a medieval nickname composed of taglia-, from tagliare ("to cut"), and ferro ("iron"), with two complementary interpretations: that of a trade —one who works or cuts iron— and that of a warrior epithet, applied to combatants capable of cleaving with a single stroke the enemy's armour or helmet.

E. De Felice specifies that this second meaning was supported by the corresponding name of Old French Taillefer, diffused in the 11th and 12th centuries through chivalric epic. In the Neapolitan dialectal form, ferro appears as fierro, which explains the variant Tagliafierro, typical of the Campania region. De Felice notes a greater frequency of Tagliaferri in Lombardy, Tuscany and Campania.

R. Brondolo frames this kind of formation within the surnames of trade or imperative nicknames, sometimes of a jocular character, habitual in northern Italy.

It is considered that the name Tagliaferro was attributed to newborns as an omen of bravery in combat, which favoured its extension as a personal name before its transformation into a surname. The variant Taliaferri is extremely rare and seems the result of transcription errors.