Annular:
: of, relating to, or forming a ring
an annular skin lesion [Merriam-Webster]
Noted in “Researchers develop unique process for producing light-matter mixture,” University of Minnesota News and Events:
Annular holes in a thin gold film filled with silicon dioxide enable ultrastrong coupling between light and atomic vibrations. This structure provides opportunities to probe molecules interacting with quantum vacuum fluctuations and develop novel optoelectronic devices.
