Bias is disproportionate weight in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair.
Biases can be learned by watching cultural contexts. People may develop biases toward or against an individual, an ethnic group, a sexual or gender identity, a nation, a religion, a social class, a political party, theoretical paradigms and ideologies within academic domains, or a species. Biased means one-sided, lacking a neutral viewpoint, or not having an open mind. Bias can come in many forms and is related to prejudice and intuition.
In science and engineering, a bias is a systematic error. Statistical bias results from an unfair sampling of a population, or from an estimation process that does not give accurate results on average.