Interpolation

The act of introducing or inserting anything, especially that which is spurious or foreign.

That which is introduced or inserted, especially something foreign or spurious.

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.

(mathematics) calculation of the value of a function between the values already known

a message (spoken or written) that is introduced or inserted; "with the help of his friend's interpolations his story was eventually told"; "with many insertions in the margins"

the action of interjecting or interposing an action or remark that interrupts