Noun

(en noun)

That part of a country which fronts or faces another country or an unsettled region; the marches; the border, confine, or extreme part of a country, bordering on another country; the border of the settled and cultivated part of a country; as, the frontier of civilization.

* 1979 , Richard Elphic and Hermann Guilomee (editors), The shaping of South African Society, 1652 - 1820 , page 297:

Unlike a boundary, which evokes the image of a line on a map and demarcates spheres of political control, the frontier is an area where colonisation is taking place....no authority is recognised as legitimate by all parties or is able to excersise undisputed control over the area.

(obsolete) An outwork of a fortification.

* Shakespeare

Palisadoes, frontiers , parapets.

Noun

(en noun)

(literally)   The arrangement of support beams that represent a building's general shape and size.

(figuratively)   The larger branches of a tree that determine its shape.

(figuratively, especially in, computing)   A basic conceptual structure.

* {{quote-magazine, year=2012, month=March-April

, author=John T. Jost , title=Social Justice: Is It in Our Nature (and Our Future)? , volume=100, issue=2, page=162 , magazine=(American Scientist) citation , passage=He draws eclectically on studies of baboons, descriptive anthropological accounts of hunter-gatherer societies and, in a few cases, the fossil record. With this biological framework in place, Corning endeavors to show that the capitalist system as currently practiced in the United States and elsewhere is manifestly unfair.}}

These ‘three principles of connexion’ comprise the framework of principles in Hume's account of the association of ideas.

(literally)   The identification and categorisation of processes or steps that constitute a complex task or mindset in order to render explicit the tacit and implicit.