in mathematics, to predict (a value of a variable at a given point) by extending a line or curve plotted on a graph from known values at previous points
to use or extend (known data or experience) in order to surmise or work out something unknown
to predict (something) by extrapolating known data or experience
to perform the act or process of extrapolating something
extrapolation /-ʹlaysh(ə)n/ noun
extrapolative /-lətiv/ adj
extrapolator noun
[extra- + -polate as in interpolate]