Ibn Ezra on Exodus 26:17/אבן עזרא על שמות כ״ו:י״ז

1TWO TENONS. The word yadot (tenons) comes from the same root as yad (hands).

2JOINED. The word meshullavot (joined) has no cognate except for the word ha-shelabbim (the stays) (I Kings 7:29).