The authors agree that this surname derives from a personal name of Germanic origin composed of two elements. R. Brondolo identifies those components as ragin, "counsel," and Heer, "army." V. Blunda develops in greater detail the original form Ragin Harja, which he translates as "host of the divine counsel" or "army of the counselling gods," noting that ragin alluded to the divine decision or will and harja to the army or host. N. Bergamo records the Latinized form Raginheri and highlights that in many medieval cases the surname indicates a noble or warrior origin; he documents it also in the Catasto intemelio and notes its attestation throughout Italy.

E. Rossoni specifies that the base medieval name was Rainerius, documented in the Codice Diplomatico of Brescia in 1150 and in Rome in 1119, in a list of presbyters and cardinals of the time of Pope Callixtus III. Both Rossoni and Blunda mention Saint Rainerius of Pisa (12th century) as a relevant hagiographic reference. As to the geographic distribution, Rossoni indicates that Raineri presents areas in north-western Italy and a probable one in the Palermo area; that Raneri is concentrated in Sicily, in the Messina, Catania and Trapani areas; and that Ranieri, for its part, has a presence throughout the national territory.