'aniridia' originates from New Latin, formed from the Greek prefix 'a-' meaning 'without, not' + 'iris' meaning 'rainbow' (the coloured part of the eye); thus literally 'without an iris'.

'aniridia' was coined in New Latin for medical use (from Greek elements 'a-' + 'iris') and was borrowed into English with little change in form or meaning.

Initially it meant 'the absence of an iris' in medical descriptions, and this specific meaning has been retained in modern usage.