Daybreak is the moment in the morning when the sun begins to rise. If you want to see the sunrise over the ocean, you have to wake up well before daybreak.
Daybreak can also be called "sunrise," "dawn," or "the break of day." It's the very first glimpse of sunlight you see in the morning, which happens very early in the summertime and later in winter. Bus drivers, morning radio hosts, and bakers often have to rise before daybreak in order to get to work on time. The break part of the word comes from the Old English root brecan, which means "shatter," but also "burst forth."