At dawn, say

EARLY

Think of a word that describes the first part of the day, often used to mean "before the usual time."

"At dawn, say" hints at a time of day when the sun first appears, which is early morning. The word "say" suggests this is just one example of something that happens at that time—like waking up early or arriving early. So, the answer is "EARLY," capturing the general idea of something occurring at the start of the day.