The authors agree that Boso is a surname derived from a personal name of Germanic origin, linked to an onomastic base of debated etymology.

A. Bongioanni describes it as a Germanic given name of obscure etymology. He considers its Germanic origin almost certain, but rejects the meaning proposed from bos or bös, which in German means "wicked", because it would perhaps be the only example of a Germanic name of hateful meaning. He proposes as an alternative hypothesis a modification of the root wis or weise, "wise" or "expert", although perhaps in contrast with the phonetic laws. He also notes that, by darkening of the vowel o, the Veneto surnames Busato, Busetto, Businelli and Busolini arise.

V. Blunda presents it as a Sicilian surname of Germanic root, derived from the personal name Bosi, a Lombard anthroponym linked to an onomastic base of debated etymology. Some hypotheses connect it with the root bos in the sense of "wicked" or "quarrelsome"; others, with a hypocoristic form of compound names. He recalls that Boso was a frequent name in the minor Carolingian dynasties, borne by Boso of Provence, king of Cisjurane Burgundy between 879 and 887, the first monarch of that political formation. The form Busi presents the usual passage o > u of northern Italian.