interpolation

The estimation of z values of a surface at an unsampled point based on the known z values of surrounding points.

The insertion of a scalar or list value somewhere in the middle of another value, such that it appears to have been there all along. In Perl, variable interpolation happens in double-quoted strings and patterns, and list interpolation occurs when constructing the list of values to pass to a list operator or other such construct that takes a "LIST".