in Philology, the parroining another man's works, and putting them off as our own. Among the Romans, plagiarius 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 plagas, "to be whipped."
Thomaeus has an express treatise De plagio literario; wherein he lays down the laws and measures of the right which authors have to one another's writings.
"Dictionary writers, at least such as meddle with arts and sciences (as is pertinently observed by Mr Chambers), seem exempted from the common laws of meum et tuum: they do not pretend to set up on their own bottom, nor to treat you at their own cost. Their works are supposed, in great measure, compositions of other peoples; and what they take from others, they do it avowedly, and in the open sun.βIn effect, their quality gives them a title to every thing that may be for their purpose, wherever they find it; and if they rob, they do not do it any other wise than as the bee does, for the public service. Their occupation is not pillaging, but collecting contributions; and, if you ask them their authority, they will produce you the practice of their predecessors of all ages and nations."