Morphism
A morphism can be thought of as a function, a key-value pair, a causal relation, or a general refers to either function, functor, or natural transformation.
Type of Mathematical objects
In PKC, we consider morphism, like function, as a type of terminal object in the space of mathematical object types. We consider it to be the last object to be interpreted in terms of object types, because it is considered to be a universal component in mathematical expressions.