in Geometry, is the same with what is otherwise called the perimeter of a figure.

AMBIT was particularly used in Antiquity to denote a space of ground to be left vacant between one building and another. By the laws of the twelve tables, houses were not to be built contiguous, but an ambit or space of 2½ feet was to be left about each for fear of fire. The ambitus of a tomb or monument denoted a certain number of feet in length and breadth around the same, within which the sanctity assigned to it was limited. The whole ground wherein a tomb was erected was not to be secreted from the common uses; for this reason, it was frequent to inscribe the ambit on it, that it might be known how far its sanctity extended: thus, in fronte pedes tot, in agrum pedes tot.