'anomalistical' originates from English formation based on 'anomalistic'/'anomaly', ultimately from Greek 'anōmalía', where 'a-' meant 'not' and 'homalos' meant 'even or level'.

'anomalistical' developed in modern English from the noun 'anomaly' (via Latin and French forms from Greek 'anōmalía'); the adjective forms 'anomalous' and 'anomalistic' preceded and influenced 'anomalistical'.

Initially tied to the Greek sense of 'not even' or 'unevenness', the term evolved to mean 'deviating from the norm' or 'irregular' in modern English usage.