It is common to define a subject as an object of study. Thus the reason we say we change subjects if a topic is changed. In the Subjations system however, a subject is a cross-utilized unit of a relation. This new definition is not much different than being an object of study but it includes the reason that elements of a topic are relevant or related.

By defining a subject as a cross-utilized unit of a relation instead of as an object of study the concept of dimensionality comes into play. Objects of study are one dimensional just as the units of a graph are of the first dimension along the x-axis of a Cartesian coordinate system. When we include the concept of relations into the definition of a subject, the event of creating a relation is much like a function. Functions are, after all, relations. Therefore, a relation is nothing more than being in the second dimension or in the y-axis. The y-axis in mathematics is the functional mapping of the x-axis, y = f(x).

The next dimension, the z-axis, contains multiple relations. But that is it, there are no more dimensions. The first dimension are subjects, the second dimension are relations and the third is multiple relations. No more dimensions are possible. In this way, if one says that a subject is an object of study, then this person has a one-dimensional mind. To say that a subject is a cross-utilized unit of a relation is a sign of a three-dimensional mind.