Distance, or farness, is a numerical description o hou far apart objects are. In pheesics or everyday uisage, distance mey refer tae a pheesical length, or an estimation based on ither criteria (e.g. "twa coonties ower"). In mathematics, a distance function or metric is a generalization o the concept o pheesical distance. A metric is a function that behaves accordin tae a specific set o rules, an is a concrete way o describin what it means for elements o some space tae be "close tae" or "far away frae" each ither. In maist cases, "distance frae A tae B" is interchyngeable wi "distance atween B an A".