וּדְמ֞וּת עַל־רָאשֵׁ֤י הַחַיָּה֙ רָקִ֔יעַ כְּעֵ֖ין הַקֶּ֣רַח הַנּוֹרָ֑א נָט֥וּי עַל־רָאשֵׁיהֶ֖ם מִלְמָֽעְלָה׃
И над головами живых существ было подобие небосвода, подобного цвету ужасного льда, простиравшегося над их головами над головой.
Chagigah
This one refers to that which is within, and this one refers to that which is outside. And Rabbi Acha the son of Ya'akov said, "There is another firmament above the heads of the chayot, as it is written, 'And a figure on top of the head of the chaya; a firmament, like the appearance of the great snow (Ezekiel 1:22).'