Definition of "interpolation"
noun
countable and uncountable, plural interpolations
(editing, content analysis) That which is introduced or inserted; in contexts of content analysis of centuries-old texts, especially something foreign or spurious.
Quotations
We, who are born into the world's artificial system, can never adequately know how little in our present state and circumstances is natural, and how much is merely the interpolation of the perverted mind and heart of man.
1843, Nathaniel Hawthorne, “The New Adam and Eve”, in Mosses from an Old Manse. […], part II, New York, N.Y.: Wiley and Putnam, published 1846, page 1