Quiz: Remember the definition of mal de mer?
1560s, from Latin halo (nominative halos), from Greek halos "disk of the sun or moon, ring of light around the sun or moon" (also "threshing floor" and "disk of a shield"), of unknown origin. Sense of "light around the head of a holy person or deity" first recorded 1640s. As a verb from 1801.
halo ha·lo (hā'lō)
n. pl. ha·los or ha·loes
A reddish yellow ring surrounding the optic disk, caused by an expansion of the scleral ring that makes the deeper structures visible.
A ring of light surrounding a luminous body.