'argillic' originates from Latin, specifically the word 'argilla', where 'argilla' meant 'clay'.

'argilla' came from Greek 'argillos'; through Latin forms and the adjective 'argillaceous' in English, the specialized adjective 'argillic' was later coined (especially in 20th-century soil science) to describe clay-enriched horizons.

Initially it referred to 'clay' or 'relating to clay', but over time it evolved into the current technical sense of 'relating to or characterized by clay, especially a subsurface soil horizon enriched in clay'.