'pupillary' originates from Latin, specifically the word 'pupilla', where 'pupilla' meant 'little doll' (a diminutive of 'pupus') and was used for the small reflected image seen in the eye (hence 'pupil').

'pupillary' changed from the Middle English word 'pupil', which was borrowed from Old French 'pupille' and Medieval Latin 'pupilla', and eventually the modern English adjective 'pupillary' was formed by adding the suffix '-ary'.

Initially, it meant 'little doll' (and by extension a small image or a child), but over time it evolved into meanings related to 'pupil' and now commonly means 'relating to the pupil of the eye'.