'Boundary', an edge in the topology of manifolds, as in the case of a 'manifold with boundary'

Boundary in surveying is the dividing line between parcels of land, and the subject of a 'boundary survey'

Boundary (cricket), the border of the field in the sport of cricket

Boundary (topology), the set of points in the closure of a subset of a topological space

A border that encloses a space or an abstract concept

Boundaries (film), a 1997 movie starring Playboy 'playmate' Kathy Shower

Boundaries in landscape history, the divide between areas of differing land use

Boundary (thermodynamic), the edge of a thermodynamic system across which heat, mass, or work can flow

Boundaries (television), a 2008 television series.