'pro-episcopal' originates from the Latin prefix 'pro-' meaning 'for' (from Latin 'pro') combined with 'episcopal', which ultimately derives from Greek 'episkopos' meaning 'overseer' or 'bishop'.

'episkopos' (Greek) became Latin 'episcopus' (meaning 'bishop'), which gave rise to the adjective 'episcopal' in Medieval/Modern English; the compound 'pro-episcopal' was formed in English by adding the prefix 'pro-' to 'episcopal' to indicate being 'for' bishops.

Initially 'episkopos' meant 'overseer'; over time this came to mean 'bishop' in church contexts, and 'episcopal' came to mean 'relating to bishops'; 'pro-episcopal' therefore came to mean 'in favor of bishops' or 'supportive of episcopal governance'.