noun. A growing rubescent or red; the state of becoming or being red; a blush.

noun. The quality or state of being rubescent; a reddening; a flush.

noun. a reddening.

"Ahead the mist deepened into a ruddier glow; through it a long, dark line began to appear — the mouth I thought of the caverned space through which we were going; it was just before us; over us — we stood bathed in a flood of rubescence!"

flush  reddening