bor·der / ˈbôrdər/ • n. 1. a line separating two political or geographical areas, esp. countries: Iraq's northern border with Turkey.2. the edge or boundary of something, or the part near it: the northern border of their distribution area. 3. a band or strip, esp. a decorative one, around the edge of something: put a white border around the picture.• v. [tr.] form an edge along or beside (something): a pool bordered by palm trees. ∎  (of a country or area) be adjacent to (another country or area): regions bordering Azerbaijan. ∎  [intr.] (border on) fig. be close to an extreme condition: Sam arrived in a state of excitement bordering on hysteria. ∎  (usu. be bordered with) provide (something) with a decorative edge: a curving driveway bordered with chrysanthemums.

border a boundary; especially the Border, the boundary and adjoining districts between Scotland and England, which especially between the 15th and the 17th centuries was a lawless area requiring particular management. The term seems to have originated in Scotland, where the border with England, being the only one it had, became known as the border. The political importance of the Border disappeared after James VI of Scotland inherited the English crown in 1603.
Border States in the US, states such as Delaware, Maryland, Kentucky, and Missouri, in which slavery was legal, but which did not secede from the Union during the Civil War.

border XIV — OF. bord(ë)ure — CRom. deriv. of *bordāre (F. border, etc.), f. *bordus; see BOARD, -URE.
Hence border vb. XIV.