The convergence of multiple technologies including geographic information systems (GIS), Internet, wireless communications, location determination, and portable devices has given rise to exciting new types of information utilities that may be referred to simply as location services. Also called mobile location services, wireless location services, or location based services, these systems are making a major impact on how we navigate our world and how business is done. Knowing where a person or object is at any time presents a powerful new dimension to the kinds of information services that can be offered. Location services deliver geographic information between mobile and/or static users via the Internet and/or wireless network.
[source: Ian Koeppel, ESRI]
Location: Identifiable geographic place re-presented by any one of a set of data types that describe a position, along with metadata about that data. A location is represented by one of a set of data types that describe a position, along with metadata about that data, including coordinates (from a coordinate reference system), a measure (from a linear referencing system), or an address (from an address system).
[source: ISO 19112:2003 Geographic information – Spatial referencing by geographic identifiers]
Location Based Service: Service whose return or other property is dependent on the location of the client requesting the service or of some other thing, object or person.
[source: ISO 19133:2005 Geographic information – Location-based services – Tracking and Navigation]