Webster's Revised Unabridged Dictionary · 1913

Abnormal

Abnormal ({not transcribed}) , adjective

[For earlier anormal, French anormal, Late Latin anormalus for anomalus, Greek {not transcribed}. Confused with Latin abnormis. See Anomalous, Abnormous, Anormal.]

Not conformed to rule or system; deviating from the type; anomalous; irregular.
That deviating from the type; anomalous; irregular. — Froude