The word “juglans” = “walnut” is commonly said to be come from “Iovis glans” = “Jupiter’s nut”; but a walnut kernel (see https://draxe.com/wp-content/uploads/2019/04/walnuts_article.gif) is in two halves joined by a thin neck, which easíly breaks when the nut is extracted from its shell; and that got me wondering whether “iuglans” came from “iugum” + “glans” = “yoke nut” or “joined nut” or “paired nut”.
Checking the TLL, it appears that Verrius Flaccus (see https://en.wikipedia.org/wiki/Verrius_Flaccus) calls it “iugulandam”, because otherwise it is separated in the middle. The entry points to Sextus Pompeius Festus’ epitome and his article on the word ‘naucum’:
https://babel.hathitrust.org/cgi/pt?id=njp.32101077773990&view=1up&seq=226