'atrichic' originates from Greek, specifically the word 'ἄτριχος' (atrichos), where the prefix 'a-' meant 'without' and 'thrix/trich-' meant 'hair'.

'ἄτριχος' (Greek) passed into New/Modern Latin forms such as 'atrichia'/'atrichicus' and was adopted into English as the technical adjective 'atrichic'.

Initially it meant 'without hair' in Greek, and over time it has retained essentially the same meaning in medical and technical English as 'lacking hair'.