Unit Definition (feet [international, U.S.])
The human foot has long been a standard unit for the measurement of length. Over history this size has varied from region to region and there is some discrepancy as to an exact standard or origin of the standard measurement for feet that we use today. In England, the Roman foot was replaced after the fall of Rome by the natural foot. The modern foot (1/3 yard or about 30.48 centimeters) did not appear until after the Norman conquest of 1066. It may be an innovation of Henry I, who reigned from 1100 to 1135. Later in the 1100's a foot of modern length, the "foot of St. Paul's," was inscribed on the base of a column of St. Paul's Church in London.

Unit Definition (point [Didot])
The point is a unit of length used by typographers and printers. When printing was done from hand-set metal type, one point represented the smallest element of type that could be handled, roughly 1/64 inch. Eventually, the point was standardized in Britain and America as exactly 1/72.27 = 0.013 837 inch, which is about 0.35 mm (351.46 micrometers). In continental Europe, typographers traditionally used a slightly larger point of 0.014 83 inch (about 1/72 pouce, 0.377 mm, or roughly 1/67 English inch), called a Didot point after the French typographer Firmin Didot (1764-1836). In the U.S., Adobe software defines the point to be exactly 1/72 inch (0.013 888 9 inch or 0.352 777 8 millimeters), a unit sometimes called the big point (bp). The German standards agency DIN has proposed that all these units be replaced by multiples of 0.25 millimeters (1/101.6 inch).