Meaning of INTERPOLATION in English

INTERPOLATION

[noun] [formal]Dorothy Rose has edited this book, supplying a foreword and informed interpolations in the text. [C]During a comic introductory chorus, he was supposed to step forward with the shouted interpolation, "Oh, Mrs Gibson!" [C]The writer did not sympathize with the interpolation of religion into affairs of state. [U]

Cambridge English vocab.      Кембриджский английский словарь.