extrapolation (n.)youdaoicibaDictYouDict[extrapolation 词源字典]
1867, noun of action from extrapolate by analogy of interpolation; original sense was "an inserting of intermediate terms in a mathematical series." Transferred sense of "drawing of a conclusion about the future based on present tendencies" is from 1889.[extrapolation etymology, extrapolation origin, 英语词源]