Distance is a numerical description of how far apart objects are. In physics or everyday usage, distance may refer to a physical length, or an estimation based on other criteria (e.g. "two counties over"). In mathematics, a distance function or metric is a generalization of the concept of physical distance. A metric is a function that behaves according to a specific set of rules, and is a concrete way of describing what it means for elements of some space to be "close to" or "far away from" each other. In most cases, "distance from A to B" is interchangeable with "distance between B and A".
Overview and definitions
A physical distance can be mean several different things:
The length of a specific path traveled between two points, such as the distanced walked while navigating a maze
The length of the shortest possible path through space between two point that could be taken if there were no obstacles (usually formalized as Euclidean distance)
Dashed black lines: Uncertain calibration ladder step.
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are "close enough" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.
The term "flat" is relative when speaking of tables, and often the naming or identification of a table (or table hill or mountain) is based on the appearance of the terrain feature from a distance or from below it. An example is Mesa Verde, Colorado, where the "flat top" of the mountain is both rolling terrain and cut by numerous deep canyons and arroyos, but whose rims appear quite flat from almost all directions, terminating in cliffs.
Motions which use the word "table" have specific meanings and functions, depending on the parliamentary authority used. The meaning of "table" also depends on the context in which it is used.
Difference between American and British usage
Both the American and the British dialects have the sense of "to table" as "to lay (the topic) on the table", or "to cause (the topic) to lie on the table". A related phrase "put on the table" has the same meaning for both dialects, which is to make the issue available for debate. The difference is when "table" is used as a verb.
The British meaning of to "table" is to begin consideration of a proposal. This comes from the use of the term to describe physically laying legislation on the table in the British Parliament; once an item on the order paper has been laid on the table, it becomes the current subject for debate.