Correct spelling for the English word "Yernut" is [jˈɜːnʌt], [jˈɜːnʌt], [j_ˈɜː_n_ʌ_t] (IPA phonetic alphabet).
There doesn't appear to be any widely recognized etymology or origin for the word "Yernut" in English. It does not seem to be a commonly used or documented term. It's possible that "Yernut" could be a misspelling or a neologism for which no established etymology exists.