Etymology tree Proto-Italic *wre- Latin re-der. Old French re-bor. Middle English re- English re- English inforce English reinforce Proto-Indo-European *-yósder. Proto-Italic *-āzijos Latin -āriusnom. Latin -āriusbor. Proto-Germanic *-ārijaz Proto-West Germanic *-ārī Old English -ere Middle English -ere English -er English reinforcer From reinforce + -er.