Geofence

Part of speech: noun, verb

Definitions

1. A virtual perimeter established around a specific geographic area that automatically triggers an alert or action when a device enters or exits it
2. A digital boundary set on a map that activates a predetermined response when a mobile device or object crosses its edges
3. An invisible electronic border around a location that causes an automated function to activate when someone with a tracked device breaches it

Etymology: "Geofence" is a plain compound: "geo-" (from Greek "gē", earth) joined to "fence." The result describes a virtual boundary drawn around a real place on a map, which a GPS-enabled device or app can detect when it crosses in or out. The fence itself is an ordinary wooden or wire barrier, but here it exists only as coordinates in software. The word works as both a noun and a verb. As a noun it names the boundary itself, while as a verb it means to set up such a boundary around a location, so a business might geofence a shopping district to send offers to nearby phones. The "geo-" prefix is the same one found in "geography" and "geology," which is why the term reads as "earth-fence" even though the physical barrier it borrows its name from never has to exist.

Synonyms: boundary, perimeter, limit, barrier