Relating to or of the nature of the firmament; pertaining to the visible sky or the heavens.
From 'firmament' (from Latin 'firmamentum' meaning 'support' or 'vault of heaven') plus adjective suffix '-al' (from Latin '-alis'). Describes qualities related to the sky or heavens.
Medieval people used 'firmamental' to describe anything in the realm of the stars and sky—and fascinatingly, the word 'firmament' comes from Latin meaning 'fixed' or 'solid,' because people genuinely thought the sky was a solid dome holding up the heavens.
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