'proctoscopic' originates from Greek, specifically the element 'prokt-' from 'proktos' meaning 'anus, rectum', combined with the combining form from Greek 'skopein' (via '-scopic') meaning 'to look' or 'to examine'.

'proktos' (Greek) + 'skopein' (Greek) gave New Latin/medical formation 'proctoscopy' (the examination), from which the adjective 'proctoscopic' was formed in modern medical English.

Initially it denoted something 'for examining the rectum' (an examination or the instrument-related sense); over time it has been used as an adjective meaning 'relating to or used in proctoscopy,' a meaning that has largely been retained.