[1] In lower case this word is a Greek transliteration of the Latin carbo, coal, but Adler printed it in upper case, probably rightly, to make it a cognomen in the Roman family of the Papirii. (For several Papirii Carbones active in the last century of the Republic, and attested in Greek sources such as Appian and Plutarch, see OCD(4) s.v. Papirius.)
[2] cf. alpha 2522. (For the connection between this and the beginning of the entry, not made explicit, see the preceding note.)