What is the vowel associated with the letter “dalet” in the name “Aleph-Dalet-Nun-Yud”? I always assumed it was a “cholam” (see here for example) but someone who is (otherwise) careful in his pronunciation seems to make it a “kometz” or maybe a “patach”. Sourced answers vastly preferred.
There are two different names you may be referring to. In Genesis 19:2 it says:
וַיֹּאמֶר הִנֶּה נָּא-אֲדֹנַי, סוּרוּ נָא אֶל-בֵּית עַבְדְּכֶם וְלִינוּ וְרַחֲצוּ רַגְלֵיכֶם, וְהִשְׁכַּמְתֶּם, וַהֲלַכְתֶּם לְדַרְכְּכֶם; וַיֹּאמְרוּ לֹּא, כִּי בָרְחוֹב נָלִין
and he said: 'Behold now, my lords, turn aside, I pray you, into your servant's house, and tarry all night, and wash your feet, and ye shall rise up early, and go on your way.' And they said: 'Nay; but we will abide in the broad place all night.'
thereby using a patach under the nun to denote "my masters."
However in Deuteronomy 3:24 it says:
אֲדֹנָי יְהוִה, אַתָּה הַחִלּוֹתָ לְהַרְאוֹת אֶת-עַבְדְּךָ, אֶת-גָּדְלְךָ, וְאֶת-יָדְךָ הַחֲזָקָה--אֲשֶׁר מִי-אֵל בַּשָּׁמַיִם וּבָאָרֶץ, אֲשֶׁר-יַעֲשֶׂה כְמַעֲשֶׂיךָ וְכִגְבוּרֹתֶךָ
O Lord GOD, Thou hast begun to show Thy servant Thy greatness, and Thy strong hand; for what god is there in heaven or on earth, that can do according to Thy works, and according to Thy mighty acts?
thereby using a kamatz under the nun to denote "The Lord" [a name for God].
I note that there also exists that word with a chirik (Genesis 44:19) or tzeirei (I Kings 16:24) under the nun (meaning "my master" and "masters of" respectively) but I am not aware on any spelling with a cholom on the nun.
Note: in addition to showing the different vowels under the nun, these pesukim do show rather conclusively that the vowel on the dalet is always a cholom. I can't find any instance in tanach without the cholom on the dalet in the context of shem hashem.