extrapolation

/EH0 K S T R AE0 P AH0 L EY1 SH AH0 N/
noun
  1. 1

    A calculation of an estimate of the value of some function outside the range of known values.

  2. 2

    An inference about some hypothetical situation based on known facts.

  3. 3

    The diametric opposite of interpolation.

Source: https://en.wiktionary.org/wiki/extrapolation