'postocular' originates from Latin, specifically the prefix 'post-' and the word 'oculus', where 'post-' meant 'after, behind' and 'oculus' meant 'eye'.

'postocular' was formed in New/Modern Latin by combining 'post-' + a derivative of 'oculus' (e.g. 'ocularis') and entered scientific English as 'postocular' to describe structures located behind the eye.

Initially, it meant 'located after or behind the eye', and over time it has retained this anatomical/zoological meaning with little change.