What is the word origin of the word 'halogen?

The origin of this Word is Greek. "Halogen" is of Greek origin.

The Latin Word "Halo", ΑΧΛΥΣ in ancient Greek, ΑΧΤΙΣ / ΑΚΤΙΣ*/ ΑΧΤΙΔΑ / ΑΚΤΙΝΑ*/ ΑΧΛΑΔΑ in modern Greek, stands for "Blurring light" "Beam of light" "Bunch of light-beams springing from a center", "Shaft of light" (light-shaft). *ΑΚΤΙΣ / ΑΚΤΙΝΑ stands for "radius", too!

ΑΧΛΥΣ (Halo) refers to the shape resembling a pear.

The suffix -gen stands for: "Creator of" the thing signified by the affix ("Halo").