the first light of day
"we got up before dawn"
"they talked until morning"
atmospheric phenomena accompanying the daily appearance of the sun
"The vibrant colors of the sunrise were a stunning display of atmospheric phenomena accompanying the daily appearance of the sun."
the daily event of the sun rising above the horizon
"The birds began to sing as soon as the sunrise painted the sky in shades of orange and pink."
The time of day when the sun appears above the eastern horizon.
"We woke up just in time to watch the sunrise appear over the distant mountains."
In plain English: Sunrise is when the sun first appears above the horizon after being below it during the night.
"We went to watch the sunrise over the ocean before starting our hike."
Usage: Sunrise refers specifically to the moment the upper edge of the sun becomes visible, not its subsequent ascent or position in the sky. Use this term for the event itself rather than describing how high the sun has climbed after it first appeared.
Sunrise comes from Middle English sonne-rys, which is simply the combination of "sun" and "rise." The word traveled directly into modern English with its original meaning intact.