a person brilliantly outstanding in some respect
Another darling weakness of the Academy is that none of its luminaries must ‘arrive’ in a hurry … By the time they have painted a thousand or so square yards of canvas, their work begins to be recognized — Saki
a natural body that gives light, e.g. the sun or moon
[Middle English luminarye via French from late Latin luminaria, pl of luminare lamp, heavenly body, from lumin-, lumen light]