in·ter·po·late 
(ĭn-tûrpə-lāt′)
(ĭn-tûrpə-lāt′)v. in·ter·po·lat·ed, in·ter·po·lat·ing, in·ter·po·lates
v.tr.
1. To insert or introduce between other elements or parts.
2.
a. To insert (material) into a text.
b. To insert into a conversation. See Synonyms at introduce.
3. To change or falsify (a text) by introducing new or incorrect material.
4. Mathematics
a. To estimate a value of (a function or series) between two known values.
b. 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.
5. To introduce estimated values of (pixel data) into a pixel array to improve the quality of an enlarged digital image.
v.intr.
To make insertions or additions.
[Latin interpolāre, interpolāt-, to touch up, refurbish, from interpolis, refurbished; see pel-5 in the Appendix of Indo-European roots.]
in·ter′po·lation n.
in·terpo·la′tive adj.
in·terpo·la′tor n.