[ggambetta]

Also same root as "cognition". Similar in Spanish, "reconocer" and "conocer" (which also means "to meet", i.e. to know for the first time).

[jacobolus]

According to Wiktionary the early Latin word was gnōscere. Old English had cnawan and cunnan.

Besides “know”, etc., modern English words “can”, “cunning”, “canny”, etc. also come from this root.