boundary

Noun

boundary (plural boundaries)

1. The dividing line or location between two areas.
   • So this was my future home, I thought![…]Backed by towering hills, the but faintly discernible purple line of the French boundary off to the southwest, a sky of palest Gobelin flecked with fat, fleecy little clouds, it in truth looked a dear little city; the city of one's dreams.1908, W[illiam] B[lair] M[orton] Ferguson, chapter IV, in Zollenstein, New York, N.Y.: D. Appleton & Company, →OCLC, page 40
   • City or national boundaries are locations of economic opportunity, especially if the existence of the border is itself the source of a monopoly situation that favors one side over the other (Krakover, 1997).2017 October, Juin-Jen Chang, Ching-Chong Lai, Ping Wang, “A Tale of Two Cities: Cross-Border Casino Competition Between Detroit and Windsor”, in NBER WORKING PAPER SERIES, archived from the original...

   Synonyms:

   verge

2. (figuratively, in plural, often) The bounds, confines, or limits between immaterial things (such as one’s comfort zone, privacy, or professional sphere and the realm beyond).
   • I didn’t mean to push the boundaries by sending my boss a message on Saturday night.
3. An edge or line marking an edge of the playing field.
4. An event whereby the ball is struck and either touches or passes over a boundary (with or without bouncing), usually resulting in an award of 4 (four) or 6 (six) runs respectively for the batting team.
   • Travis hit a boundary to seal the match on the last ball of the over.
5. (of a set) The set of points in the closure of a set S, not belonging to the interior of that set.
6. (Philippines) Commission paid by a bus or jeepney driver to a public transportation operator for taking passengers, or the excess collected fares taken as daily wage.