'appt' originates from English, specifically the word 'appointment', where 'appt' is an abbreviation of 'appointment'.

'appointment' changed from Old French word 'apointement' and eventually became the modern English word 'appointment' through Middle English.

Initially, it referred to the act or result of appointing or assigning someone to a post or task, and over time it evolved into its current common meaning of 'a scheduled meeting or arrangement'.