A while back, I read an article that mentioned how certain words, like "Guardian" and "Warden", both entered English as different forms of the same original word.
E.g. The original French word "guarder" mutated into "warder" in Norman French, but both variants entered English at different times in history, and both forms survive today. There are undoubtedly other examples in English and in other languages.
The article also used a single word that described this phenomenon, but I can't remember what it is. "Cognate" seems like a fair description, but I seem to remember there being a more specific way to describe the same word in two different forms in the same language.
Does anyone know of a word that describes this exact phenomenon?