the Berasit Hebrew Dictionary

שנהימ

re-analyze this, given that iomim is just days

Most translations interpret this simply as “years”, but this seems somewhat problematic as it does not adequately address the inherent implications of the im suffix. Based on the root word seneh and the typical meaning of the im suffix, this word literally means “the Periodic Ones”¹⁾, or possibly “the Annual Ones”.

There is abundant contextual evidence that many instances of the word senim are misspellings of 'senehim'.