light of dawn; dawn light
A somewhat literary or poetic term for the first light of morning. In everyday speech, 夜明けの光 or 朝日 are more common.
The light of dawn began to shine in the eastern sky.
Compound of 暁 (ぎょう, 'dawn') and 光 (こう, 'light'). The reading ぎょう for 暁 is the kan'on reading, used in literary compounds.