Beast Era

Beast Era is loosely-defined fan terminology. It roughly means "the years of Beast Wars and Beast Machines", and is most often used to describe the two franchises as a single entity, much as the term Unicron Trilogy encompasses Armada, Energon, and Cybertron.

The term is also sometimes used to refer to the in-fiction time period during which the Beast cartoons take place. That is, a time roughly 300 years after the end of the great wars -- the "home" time of the BW characters, and the time to which they returned at the end of the Beast Wars cartoon.

From Teletraan I: The Transformers Wiki, a Wikia wiki.