noun.
The act of interpolating; the insertion of new words or expressions in a book or manuscript; especially, the falsification of a text by spurious or unauthorized insertions.
noun.
That which is interpolated; new or (especially) spurious matter inserted; an unannounced or unauthorized insertion in a text.
noun.
In mathematics, the process of finding, from the given values of a function for certain values of the variable, its approximate value for an intermediate value of the variable.