Weighting refers to statistical adjustments made to survey data in order to make data a more accurate representation of the population of interest. This process can correct unequal selection probability, or to compensate for survey nonresponse.
Bethlehem, J. (2008). Weighting. In P. J. Lavrakas (Ed.), Encyclopedia of survey research methods (pp. 958-960). Thousand Oaks, CA: SAGE Publications, Inc. https://doi.org/10.4135/9781412963947.n632