boundary
Pluralboundaries
- 1A dividing line or place marking where one area ends and another begins.
Surveyors spent the morning marking the boundary between the two properties.
A chain of mountains forms the boundary separating the two regions.
Similarborder, line, frontier, limit, borderline
Note
The territorial sense, built from bound, an old word for a limit, plus the suffix -ary, with roots running back through Old French to Latin. It stretches from a surveyor's property line to the edge of a nation, as in W. B. M. Ferguson's "purple line of the French boundary" in Zollenstein (1908). City and national boundaries are where two jurisdictions meet, and the word often travels alongside border.
- 2A limit marking off something nonphysical, such as your privacy, comfort zone, or professional role, from what lies beyond it.
Therapists often help clients establish healthy boundaries with demanding relatives.
He crossed a professional boundary by asking his coworker such personal questions.
Note
Here the line is drawn around a person rather than a piece of land, and the word usually goes plural: people set, establish, respect or push their boundaries. "Pushing the boundaries" can be praise for an artist or a mild confession of overstepping, such as messaging a boss on a Saturday night. In the singular it tends to name one specific limit that was crossed.
- 3An edge of the playing field, or the line that marks it.
The fielder chased the ball all the way to the boundary.
A painted rope usually marks the boundary on a cricket ground.
Note
A cricket ground's edge is usually a rope or a painted line. Inside it the ball stays in play, and reaching it changes the scoring. The word for the edge also became the word for the shot that reaches it, which is why commentators can say a batter "found the boundary" and "hit a boundary" in the same breath. The second phrase is the scoring stroke.
- 4In cricket, a scoring shot in which the ball reaches or clears the field's edge, earning the batting team four or six runs.
She struck three boundaries in a single over.
A late boundary off the final ball won the match.
Note
Named after the field's edge, this is a countable event: a batter hits, strikes or scores boundaries, and a commentator may tally them across an over or an innings. The two values depend on the ball's path. If it reaches the rope along the ground or after bouncing, it is usually worth four runs. If it clears the rope on the full, it is usually worth six.
- 5In topology, the set of points lying in a set's closure but not in its interior.
The boundary of an open disk is the circle that encloses it.
Topologists often compute the boundary of a given subset.
Similarfrontier
Note
Topology defines it through neighborhoods: a point lies on the boundary when every neighborhood of it, however small, meets both the set and its outside. A closed set contains its whole boundary and an open set contains none of it, which is why an open disk leaves out its rim. The results can surprise, since the rational numbers have the entire real line as their boundary. It is written ∂S.
- 6In Philippine usage, the fixed sum a bus or jeepney driver pays the vehicle operator from the day's fares, with any excess kept as wages.
Many jeepney drivers struggle to meet the daily boundary when passengers are few.
The operator raised the boundary, leaving drivers with thinner earnings.
Note
Philippine English uses the word for the arrangement between a bus or jeepney driver and the vehicle's operator. The driver pays a fixed sum from the day's fares and keeps whatever is left. The word can name either side of that split: the remittance owed to the operator, or the surplus fares the driver takes home as wages. Drivers speak of meeting or paying the boundary.
Practice
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Origin
Formed from "bound" plus the suffix "-ary," which traces back through Old French to Latin.