Reference for Sanhedrin 115:13

אמו אמו ממש היינו באשתו ולא באשת חברו אמו מאנוסתו

The Master stated: 'R. Eliezer said: His father means 'his father's sister'. But may it not mean his father literally?<span class="x" onmousemove="('comment',' Thus prohibiting pederasty. ');">¹³</span>

Jastrow

Jastrow