What does bias mean?
Bias is a noun describing an inclination, tendency, or prejudice — usually an unfair or distorted one — for or against a person, group, idea, or outcome. In everyday usage it most often carries negative connotations, implying that judgement has been swayed by factors such as personal preference, social conditioning, or self-interest rather than evidence or fairness. The word is central to modern discussions of psychology and society: terms like "confirmation bias," "cognitive bias," and "unconscious bias" name systematic errors in human thinking that shape decisions without our awareness. Beyond this moral sense, bias also has precise technical meanings. In statistics and machine learning, it denotes a systematic deviation of estimates or predictions from true values. In electronics, it refers to a fixed voltage applied to a circuit component to control how it operates. In textiles, cutting cloth "on the bias" means cutting diagonally across the weave so it drapes with greater stretch. This range makes bias a versatile and essential term across both everyday conversation and specialist fields.
An unfair or disproportionate inclination or prejudice for or against someone or something.
"The panel was chosen carefully to avoid any bias in the selection process."
To unfairly influence or prejudice someone or something; to cause a result or process to be systematically skewed.
"Leading questions can bias respondents' answers in a survey."
The past participle "biased" is widely used as an adjective meaning prejudiced or influenced unfairly.
A diagonal or oblique direction, especially the direction across the grain of woven fabric.
"The dressmaker cut the silk on the bias so it would drape smoothly."
Used when referring to multiple distinct instances of partiality or distortion, e.g., different types of cognitive biases.
"Researchers must account for their own biases when interpreting data."
The word "bias" comes from the same ancient root as "diagonal" — it originally meant a slanted line before it came to mean a slanted mind.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bias
"Bias" entered English in the early 16th century from French "biais", meaning a slant or oblique line, which likely traces back through Old Provençal to Latin roots connected with two lines crossing at an angle. Its original sense was literally geometric — a diagonal cut across woven fabric — and from this physical notion of slantedness developed the figurative sense of a slanted or prejudiced mind, attested by the mid-17th century. The related adjective "biased" followed shortly after.
Related word forms
How bias is actually used
"Bias" is common in formal contexts such as journalism, law, research methodology, and social commentary. As an uncountable noun it refers to the quality of partiality; as a countable noun it refers to a specific instance of it (e.g., "a gender bias"). In everyday speech it is frequently paired with adjectives like "unconscious," "implicit," "cognitive," or "political."
Easily confused with bias
"Biass" is not a standard English word; the correct noun and verb spelling is "bias", while "biased" is its adjective form.