IPA: //ˌkɔːr.əˈskeɪ.ʃən//
KK: /kɔːrʌsˈkeɪʃən/
A sudden burst of bright light or brilliance, often seen as a sparkle or flash.
The coruscation of the stars lit up the night sky beautifully.
Coruscation is formed from "coruscare" (meaning to flash or glitter) and the suffix "-tion" (indicating the action or process of). The word describes the action or process of flashing or glittering light.
Imagine a bright light that 'flashes' ('coruscare') — that's what coruscation means, the action of shining or glittering.