'pro-oxidant' originates from the prefix 'pro-' (from Latin 'pro', meaning 'for' or 'in favor of' / 'promoting') combined with 'oxidant', which comes via Modern Latin 'oxidans' and French 'oxydant'. The element 'oxy-' ultimately traces to Greek 'oxys' meaning 'sharp' or 'acid' and in chemical usage is associated with oxygen.

'oxidant' developed from French 'oxydant' (present participle) and Modern Latin 'oxidans'; the English scientific compound 'pro-oxidant' was formed by prefixing Latin 'pro-' to that base in modern usage, yielding the current English term 'pro-oxidant' and its plural 'pro-oxidants'.

Initially it referred generally to something that causes or promotes oxidation; over time it has remained a technical term in chemistry and biology for agents that promote oxidation or oxidative stress, with the core meaning largely unchanged.