'acad' originates from the English word 'academic', which in turn comes from the Latin 'academicus', derived from the Greek 'akadēmos'.

'academic' transformed from the Latin word 'academicus' and eventually became the modern English word 'academic', with 'acad' as a colloquial abbreviation.

Initially, it meant 'pertaining to an academy or school', and this meaning has largely remained the same in modern usage.