: an act of interpolating something or the state of being interpolated : the introduction or insertion of something spurious or foreign
… versions disfigured by the frequent and substantial interpolation of freely invented matter … Bernard Knox
b
: something that is introduced or inserted : an insertion or addition
How can such interpolations be identified, and what literary processes led to these additions? Jan Nattier
2
: the process of calculating an approximate value based on values that are already known
The age of tephras that were not directly dated was estimated by linear interpolation from the calibrated date. Richard J. Payne and Jeffrey J. Blackford