According to classical Indian philosophy, the source of knowledge based on cognition of an object as similar to another object already known to the cognizer is called:

The source of knowledge described is comparison, upamana.

It gives knowledge of an object through its likeness to something already known.

One learns a new thing by recognising its similarity to a familiar thing.

The relation grasped is the resemblance between the known and the newly cognised.

Knowing a wild gavaya from its likeness to a cow is the classic instance.

Cognition resting on such similarity is upamana, comparison.