is a - asserts that the thing on the left belongs to the class on the right
is called - connects a formal identifier (left) to an informal human-readable name (right)
is a subclass of - states that all instances of the class to the left are also instances of the class to the right
class - a class represents a set of concrete or abstract things
is defined as follows: - connects an identifier (left) to a human-readable definition (right)
is related to - connects two classes that are somehow related
Such a nanopublication defines a new class. Classes represent sets of concrete or abstract things, and are by convention named with singular nouns (or noun phrases) like 'human', 'cardiovascular disease', or 'approach'. If the term you want to define does not refer to a set of things but a single instance, such as the planet Mars or Marie Curie, define them with the template for individuals instead.
Defining a new class (with placeholder prefix)
URI of a class that should be treated as fully synonymous