補ほ外がい法ほうほがいほうMeanings1nounextrapolationmathematicsMathematical term for estimating values beyond a known range. Often contrasted with 補間法 (interpolation).See also: 補間法補ほ外がい法ほうを用もちいて将しょう来らいの人じん口こうを推すい定ていした。We estimated the future population using extrapolation.