What does abnormality mean?
"Abnormality" is a noun describing anything that departs from what is normal, standard, or expected — most often a physical, mental, or structural deviation identified in medical or scientific contexts, such as a chromosomal or genetic abnormality. Beyond medicine, it applies more broadly to any irregularity or anomaly, from unusual test results to oddities in data or behavior. The word carries a clinical, formal tone: it names the deviation itself rather than judging it, though in human contexts it can feel impersonal or stigmatizing compared with gentler terms like "difference." Its everyday derivatives are "abnormal," the adjective, and "abnormally," the adverb. Derived ultimately from the Latin "norma," meaning a carpenter's measuring square, the word literally invokes a standard against which things are measured. Common pairings include "detect an abnormality" and "slight abnormality," reflecting its frequent role in diagnosis and observation. It remains an essential term wherever precision about deviation matters.
A deviation from what is normal, usual, or expected, especially a physical, mental, or structural condition that differs from the typical or healthy state.
"An abnormality in the X-ray prompted further testing."
Frequently used in medical contexts; the plural "abnormalities" often refers to multiple findings in diagnostic reports.
The state or quality of being abnormal; departure from the usual or expected.
"She regarded the sudden cold snap as a mere abnormality in an otherwise mild spring."
Used when referring to multiple deviations, especially in medical or scientific findings.
"The report listed several abnormalities in the blood work."
The word traces back to Latin "norma," a carpenter's square — so to call something abnormal is literally to say it doesn't measure up to the builder's rule.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of abnormality
"Abnormality" derives from "abnormal," which combines the Latin prefix "ab-" (away from) with "norma," the Latin word for a carpenter's square or rule used as a standard of measurement. The adjective "abnormal" entered English around the early 19th century, with "abnormality" following shortly after as its noun form. Other English descendants of "norma" include "normal," "norm," and "normalize," all of which share the underlying idea of a measured standard.
Related word forms
How abnormality is actually used
"Abnormality" is largely neutral-to-formal in register and appears frequently in medical, scientific, and statistical writing. It can carry a slightly clinical or stigmatizing tone when applied to people, so careful writers often prefer "difference" or "atypicality" in sensitive contexts. The plural "abnormalities" is common in medical reports referring to multiple findings.
Easily confused with abnormality
"Abnormally" is an adverb meaning in a way that deviates from normal (e.g. abnormally large), while "abnormality" is the noun denoting the deviation itself.