  Knowledge graphs and ontologies are becoming increasingly important in the
context of making data and metadata findable, accessible, interoperable, and
reusable (FAIR). We introduce the concept of Semantic Units for organizing
Knowledge Graphs into identifiable and semantically meaningful subgraphs. Each
Semantic Unit is represented in the graph by its own resource that instantiates
a Semantic Unit class. Different types of Semantic Units are distinguished, and
together they can organize a Knowledge Graph into different levels of
representational granularity with partially overlapping, partially enclosed
subgraphs that users of Knowledge Graphs can refer to for making statements
about statements. The use of Semantic Units in Knowledge Graphs supports making
them FAIR and increases the human-reader-actionability of their data and
metadata by increasing the graph's cognitive interoperability by increasing its
explorability for a human reader. We introduce a minimal prototype web
application for a user-driven FAIR Knowledge Graph that is based on Semantic
Units.
