An entity is something that exists as itself. It does not need to be of material existence. In particular, abstractions and legal fictions are usually regarded as entities. In general, there is also no presumption that an entity is animate, or present.
The term is broad in scope and may refer to animals; natural features such as mountains; inanimate objects such as tables; numbers or sets as symbols written on a paper; human contrivances such as laws, corporations and academic disciplines; or supernatural beings such as gods and spirits.
The adjectival form is entitative.
Etymology
The word entity is derived from the Latin entitas, which in turn derives from the Latin ens meaning "being" or "existing" (compare English essence). Entity may hence literally be taken to mean "thing which exists".
Ontology is the study of concepts of existence, and of recognition of entities. The words ontic and entity are derived respectively from the ancient Greek and Latin present participles that mean "being".
In an ontic inquiry... one asks about the properties or the physical relations and structures peculiar to some entity – in the pen's case, for example, we might make the following ontic observations about it: it is black, full of blue ink, and sitting on top of my desk.[1]
In medicine, a disease entity is an illness due to a particular definite cause or to a specific pathological process. While a disease entity is not defined by a syndrome, it may or may not be manifest in one or more particular syndromes.
In computer science, an entity is an object that has an identity, which is independent of the changes of its attributes. It represents long-lived information relevant for the users and is usually stored in a database.
