mareel
Seafire, phosphorescence on the ocean, especially around the Shetland Islands.
uncountable
[…] as bright As the sheenin' mareel o' the sea.
Where it comes from
From an unattested Norn term *mareld, from Old Norse mǫrueldr, from marr (“sea”) + eldr (“fire”). Compare Icelandic maurildi, Swedish mareld.
Adapted from the Wiktionary entry mareel (CC BY-SA 4.0).