"For the purposes of your education at Beacon, 'Semblance' is defined as the power of archetype." Gotthard turns on her heel, a stick of chalk picking up the slack on its own to make notes in an impossibly delicate 'hand'. "Professor Kay will explore this in greater detail, but for now the key lesson is that, for example, it is not even unique to humans and faunus."
She taps the Grendel illustration, to a few murmurs of confusion. "This beast has a Semblance. Indeed you could say that it is a Semblance. Its archetype and it's entire being are one and the same. It is a Grendel, and thus pursues particularly raucous partygoers and festival feasters with all the cold-minded determination of an Atlesian battle-drone. It can conceive of no other course of actions. As specimens of a Grimm species age they may become more complex, may pursue their archetypal goal with greater levels of animal cunning, but they will pursue it all the same. To do otherwise would be literally unthinkable."
It's strange to hear it laid out so academically. Strange to hear it and understand it at all to be honest. Her words bounce around in your skull, colliding and combining with the Groom's. To be a Grimm is to be the sum of your pursuits, the apex of the stories you devour. Humans have their own stories, of course, but you never even conceived that they each possessed a fragment of the same power.