'acarid' originates from Greek, specifically the word 'akari,' where 'a-' meant 'not' and 'karos' meant 'heavy sleep.'

'akari' transformed into the Latin word 'acarus,' and eventually became the modern English word 'acarid' through Middle English.

Initially, it referred to small parasitic arachnids, and this meaning has largely remained the same in modern usage.