In the previous chapter we were able to automatically process text by recognizing a limited set of entities. This chapter will introduce the world of semantics, and present step-by-step examples to retrieve and enhance text and data processing by using semantics. The goal is to equip the reader with the basic set of skills to explore semantic resources that are nowadays available using simple shell script commands.
Keywords: Ancestors; ChEBI: chemical entities of biological interest; DO: disease ontology; Entity linking; Lexicons; OWL: Web Ontology Language; Ontologies; Recursion; Semantic resources; Semantic similarity.