An entity is something that exists as itself and can be of material or non-material existence. It can refer to a single person, place, or thing about which data can be stored in a database. Here are some examples of how the term "entity" is used in different contexts:

• Philosophy: In ontology, the study of concepts of existence and recognition of entities, one asks about the properties or the physical relations and structures peculiar to some entity.

• Law and Politics: In law, a legal entity is an entity that is capable of bearing legal rights and obligations, such as a natural person or an artificial person (e.g. business entity or a corporate entity) . In politics, entity is used as a term for territorial divisions of some countries.

• Medicine: In medicine, a disease entity is an illness due to a particular definite cause or to a specific pathological process.

• Computer Science: In computing, an entity is any singular, identifiable, and separate object. It refers to individuals, organizations, systems, bits of data, or even distinct parts of a system. In data modeling, an entity is some unit of data that can be classified and have stated relationships to other entities. In the Standard Generalized Markup Language (SGML), an entity is a specific character string that has the effect of causing a formatting program to select and present a particular character or notation.

In general, an entity is an existing or real thing that has separate and distinct existence and objective or conceptual reality.