Mediators are variables which serve as the mechanism by which the independent variable affects the outcome. These variables can help to explain the relationship between independent and dependent variables.
Citation: Lewis-Beck, M., Bryman, A., & Liao, T. (2004). The SAGE encyclopedia of social science research methods (Vols. 1–3). Thousand Oaks, CA: SAGE Publications. https://doi.org/10.4135/9781412950589