n. forerunner; an indication of approach of something or someone
n. One that indicates or foreshadows what is to come; a forerunner
The crocus is an early harbinger of spring.
"Detroit should not be seen as emblematic of cities or as a harbinger of what's to come," said Clarence Anthony, executive director of the National League of Cities.
Sentence in Classic:
So saying, the veteran again dropped his head to his chest, and returned slowly toward the fort, exhibiting, by the dejection of his air, to the anxious garrison, a harbinger of evil tidings.
The Last of the Mohicans By James Fenimore Cooper Context