1. partiality: an inclination or predisposition for or against something. See also prejudice.

2. any tendency or preference, such as a response bias or test bias.

3. systematic error arising during sampling, data collection, or data analysis. See biased estimator; biased sampling.

4. any deviation of a measured or calculated quantity from its actual (true) value, such that the measurement or calculation is unrepresentative of the item of interest. —biased adj.