interpolation

noun

in·ter·po·la·tion | \in-ˌtər-pə-ˈlā-shən

plural interpolations

Definition of interpolation

1a : 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|tephra|} that were not directly dated was estimated by linear interpolation from the calibrated date.— Richard J. Payne and Jeffrey J. Blackford