abnormal

Abnormal is an adjective describing something that deviates from what is standard, typical, or expected. The term is relative to the norm used for comparison, and its interpretation depends on context. In everyday language it often carries negative connotations, but in scientific and professional discourse it is a descriptive label rather than an ethical judgment.

Abnormal originates from the Medieval Latin abnormalis, from Latin ab- (away) + norma (rule). It has long been used in medicine to refer to findings that do not conform to established health norms. Over time it has spread to other disciplines where a deviation from a reference standard is of interest.

In medicine and biology, abnormal findings may indicate disease, injury, or dysfunction. Normal ranges or reference intervals are defined from population data, and an observation outside that range is labeled abnormal until further assessment clarifies its significance. In psychology and psychiatry, abnormal psychology studies patterns of thinking, feeling, and behavior that differ from typical functioning; diagnoses depend on criteria that can vary across cultures and eras. In statistics and data analysis, abnormal data points are often called outliers or anomalous observations; the label "abnormal" can reflect statistical deviation rather than pathology. In engineering and safety contexts, abnormal operating conditions describe deviations from normal operation that may require corrective action.

Limitations: The idea of normality is inherently value-laden and context-dependent. What is considered normal can vary by population, purpose, and cultural norms, so the term "abnormal" should be used with caution to avoid stigmatization or misinterpretation.

See also: anomaly, deviation, outlier, normal distribution, norm.