An Etymological Dictionary of the German Language/Annotated/Nabe
Nabe, feminine, from the equivalent Middle High German nabe, Old High German naba, feminine, ‘nave (of a wheel)’; corresponding to Dutch naaf, aaf, nave (see Näber, Natter), Anglo-Saxon nafu, feminine, English nave, Old Icelandic nǫf, feminine, all of which have the same meaning; Gothic *naba, feminine, is by chance not recorded. Both the word and the idea are Old Aryan (primitive form nobhâ); compare Old Indian nãbhi, feminine, and nãbhya, neuter, ‘nave (of a wheel).’ Undoubtedly the cognates discussed under Nabel with the meaning ‘navel’ are primitively allied, the Indian word nâbhi just quoted also signifying ‘navel,’ as well as Lettic naba, feminine, which is exactly equivalent in sound to Old High German naba. Hence Latin umbo (for *onbo, *nobo), ‘boss (of a shield),’ may also be connected with umbilîcus, ‘navel’; compare Greek ὀμφαλός, ‘navel, boss (of a shield).’ With regard to the antiquity of the terms denoting parts of a waggon see Rad, Achse, Lünse, and Deichsel.