1. insert (something of a different nature) into something else: "illustrations were interpolated in the text"
▪ insert (words) in a book or other text, especially in order to give a false impression as to its date.
▪ alter (a book or text) by insertion of new material.
▪ interject (a remark) in a conversation: "“I dare say,” interpolated her employer"
▪ insert (an intermediate value or term) into a series by estimating or calculating it from surrounding known values.
Word Originearly 17th century: from Latin interpolat- ‘refurbished, altered’, from the verb interpolare, from inter- ‘between’ + -polare (related to polire ‘to polish’).
Method for constructing new data points between known data points
In the mathematical field of numerical analysis, interpolation is a type of estimation, a method of constructing new data points based on the range of a discrete set of known data points. Wikipedia