A software tool designed to infer logical consequences from a set of asserted facts or axioms by applying a rich set of mechanisms specified through an ontology language or a description logic language to process and interpret data. Semantic reasoners typically use first-order predicate logic to perform reasoning, which allows them to deduce new information that is not explicitly stated in the input data.
A semantic reasoner could be used to analyze a set of medical records to infer the likelihood of a patient developing a certain disease based on their symptoms and medical history. By applying logical rules and inference mechanisms, the reasoner can deduce new information about the patient’s health without being explicitly told.