The definition of a herald is a messenger or announcer. An example of a herald is a town news crier. An example of a herald is the very first flower to bloom in the spring. To herald is defined as to say or show that something is coming, or to announce the news. An example of to herald is how the circus announcer tells the audience the name of the upcoming act in the circus. An example of to herald is to write the news for a local community in a newspaper.