Definition of Entity

Definition Last Updated 17-Dec-2015 12:51

Physical Entity

A physical entity is something deemed to exist and to be identified as a thing by virtue of satisfying a particular specification embodying a description1i.e. a set of observables satisfying given criteria. over an extended spatio-temporal region that, to the limits of the methods of observation, has a closed, orientable boundary2See the technical note on physical extent in the main article.. (See the main article for discussion of the boundary condition.))

The extent of an entity is usually determined by surfaces marking sharp transitions in the values , where the definition of sharpness depends on the precision, resolution, etc. of the observations. The requirement that the bounding surfaces be closed and orientable is what makes entities countable3Thereby justifying the use of the plural..

Entity is synonymous with thing and object but distinguished from stuff. The sea is a thing; sand is stuff. Entities may have parts, i.e. comprise other distinguishable entities; to the limits of the particular observation, stuff does not have parts4October 29, 2015: some stuff, such as sand, might constitute a non-physical entity; I’m not sure yet..

Examples of physical entities include: a (specific) dog, chair, house, personnel record, CPU, magnetic field, etc.

Non-Physical Entity

A non-physical entity5October 29, 2015: the basis for describing non-physical entities is a recent addition to this entry and neither the approach nor the implementation may be as well worked-out as others; the idea that relationships might be non-physical entities seems necessary but may have untoward complications. Feedback is invited via Twitteror the contact page. is something deemed to exist and to be identified as a thing by virtue of the existence of a set of physical entities (i.e. more than one) whose elements’ relationships satisfy a particular specification that describes the elements as having

  • certain relationships in common, or
  • certain relationships between other relationships.

The set of physical entities that satisfy the specification comprise the non-physical entity, i.e. the elements of the set are variously members or parts of the non-physical entity so described.

Note that, thus defined, relationships are also non-physical entities.

Examples of non-physical entities include: a business or enterprise, school of thought, a terrorist cell,

Scope

Entity is a defined term of Enterprise Architecture. Entity is a defined term of Business Analysis.

Notes   [ + ]

1.i.e. a set of observables satisfying given criteria.
2.See the technical note on physical extent in the main article.
3.Thereby justifying the use of the plural.
4.October 29, 2015: some stuff, such as sand, might constitute a non-physical entity; I’m not sure yet.
5.October 29, 2015: the basis for describing non-physical entities is a recent addition to this entry and neither the approach nor the implementation may be as well worked-out as others; the idea that relationships might be non-physical entities seems necessary but may have untoward complications. Feedback is invited via Twitteror the contact page.

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