Effulgence is a noun for a beautiful, strong shining — light pouring out, so bright it feels almost alive. Writers use it for the sun, for gold, for a face that seems to glow. It is a high, bookish word; almost nobody says it while pointing at a lamp. In ordinary talk we say glow, shine, or brightness. Though actually, the short dictionary line “beautiful and bright” belongs more to the adjective next door (effulgent). Effulgence is the shining itself, the flood of light, not the word you put in front of a noun. Poems and grand prose love it; science class does not need it. If you use it in a chat message, it will sound like you have swallowed an old novel — which can be fun, if you mean it that way. Do not mix it with effluent (waste water). They only share a first look.

光輝、燦爛（很書面／文學；平常說很亮、很耀眼）