Webster's Revised Unabridged Dictionary · 1913

Interpolation

Interpolation , noun

[Latin interpolatio an alteration made here and there: compare French interpolation.]

1.
The act of introducing or inserting anything, especially that which is spurious or foreign.
2.
That which is introduced or inserted, especially something foreign or spurious.
Bentley wrote a letter.... upon the scriptural glosses in our present copies of Hesychius, which he considered interpolations from a later hand. — De Quincey
3.
(Mathematics) The method or operation of finding from a few given terms of a series, as of numbers or observations, other intermediate terms in conformity with the law of the series.