interpolate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To insert or introduce between other elements or parts.
• intransitive verb To insert (material) into a text.
• intransitive verb To insert into a conversation. synonym: introduce.
• intransitive verb To change or falsify (a text) by introducing new or incorrect material.
• intransitive verb To estimate a value of (a function or series) between two known values.
• intransitive verb To create a continuous function that incorporates (a finite set of data), such as creating a curve that passes through a fixed set of points or a surface through a fixed set of curves.
• intransitive verb To introduce estimated values of (pixel data) into a pixel array to improve the quality of an enlarged digital image.
• intransitive verb To make insertions or additions.

from The Century Dictionary.

• To insert in a writing; introduce, as a word or phrase not in the original text; especially, to foist in: introduce surreptitiously, as what is spurious or unauthorized.
• To alter, as a book or manuscript, by insertion of new matter; introduce new words or phrases into; especially, to corrupt or vitiate by spurious insertions or additions.
• In mathematics and physics, to introduce, in a series of numbers or observations (one or more intermediate terms), in accordance with the law of the series; make the necessary interpolations in: as, to interpolate a number or a table of numbers.
• To carry on with intermissions; interrupt or discontinue for a time.
• To interpose; place in an intermediate position.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To renew; to carry on with intermission.
• transitive verb To alter or corrupt by the insertion of new or foreign matter; especially, to change, as a book or text, by the insertion of matter that is new, or foreign to the purpose of the author.
• transitive verb (Math.) To fill up intermediate terms of, as of a series, according to the law of the series; to introduce, as a number or quantity, in a partial series, according to the law of that part of the series; to estimate a value at a point intermediate between points of knwon value. Compare extrapolate.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb mathematics To estimate the value of a function between two points between which it is tabulated.
• verb computing During the course of processing some data, and in response to a directive in that data, to fetch data from a different source and process it in-line along with the original data.
• verb transitive, intransitive To introduce (material) to change the meaning of or falsify a text.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb estimate the value of
• verb insert words into texts, often falsifying it thereby