'classificatory' originates from Late Latin, specifically the word 'classificatorius', formed from Latin 'classis' + '-ficare' (from 'facere'), where 'classis' meant 'a division or class' and '-ficare' meant 'to make/do'.

'classificatorius' passed into scholarly New Latin and then into English as 'classificatory' (via formation of English adjectival suffixes), becoming established in the modern English vocabulary in the 18th–19th centuries.

Initially it meant 'serving to make or place into classes', and over time this retained its basic sense of 'relating to classification' with specialized use in scientific and organizational contexts.