Dictionary.net

An officer among the Romans who reduced to writing and into proper form, agreements, contracts, wills, and other instruments, and witnessed their execution. The term tabellio is derived from the Latin tabula, seu tabella, which in this sense, signified those tables or plates covered with wax which were then used instead of paper. 8 Toull. n. 5; Delauriere, sur Ragneau, mot Notaire.

Tabelliones differed from notaries in many respects: they had judicia jurisdiction in some cases, and from their judgments there were no appeals. Notaries were then the clerks or aiders of the tabelliones, they received the agreements of the parties, which they reduced to short notes; and these contracts were not binding until they were written in extenso, which was done by the tabelliones. Encyclopedie de, M. D'Alembert, mot Tabellion; Jac. Law. Dict. Tabellion; Merlin, Repertoire, mot Notaire, §1; 3 Giannone's Istoria di Napoli, p. 86.