PLAGIARY, the purloiner of another man's works. Amongst the Romans, plagiarus was properly a person who bought, sold, or retained a freeman for a slave; and was so called because, by the Flavian law, such persons were condemned ad plagium, or to be whipped. Thomasius has an express treatise de plagio literario, wherein he lays down the laws and measures of the right which authors have to use one another's writings.