The main difference between Dawn and Sunrise is that the Dawn is a time that marks the beginning of the twilight before sunrise and Sunrise is a instant at which the upper edge of the Sun appears over the eastern horizon in the morning.
Dawn, from an Old English verb dagian: “to become day”, is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in the atmosphere, when the centre of the Sun’s disc reaches 18° below the horizon. This dawn twilight period will last until sunrise (when the Sun’s upper limb breaks the horizon), as the diffused light becomes direct sunlight.
Sunrise (or Sun up) is the moment when the upper limb of the Sun appears on the horizon in the morning. The term can also refer to the entire process of the solar disk crossing the horizon and its accompanying atmospheric effects.
To begin to brighten with daylight.
“A new day dawns.”
To start to appear or be realized.
“I don’t want to be there when the truth dawns on him.”
To begin to give promise; to begin to appear or to expand.
The morning twilight period immediately before sunrise.
The rising of the sun.
The time when the sun rises.
“She rose before dawn to meet the train.”
“the dawn of civilization”
The time of day when the sun appears above the eastern horizon.
“sunup|crack of dawn|dawn|sparrow-fart|q4=slang”
“I’ll meet you at the docks at sunrise.”
The change in color of the sky at dawn.
“Did you see the beautiful sunrise this morning?”
Any great awakening.
“It was the sunrise of her spirit.”
the time in the morning when the sun appears or full daylight arrives
“an hour before sunrise”
the colours and light visible in the sky on an occasion of the sun’s first appearance in the morning, considered as a view or spectacle
“a spectacular sunrise over the summit of the mountain”