Page "United States customary units" Paragraph 8

Other countries had ( or still have, unofficially ) customary units of their own, sometimes very similar in name and measure to U. S. customary units, since they often share the same Germanic or Roman origins.

Frequently, however, these units designate quite different sizes.

For example, the mile ranged by country from one half to five U. S. miles ; even foot and pound had varying definitions.

Until the twentieth century the customary units of measure in the United States were sometimes just as variable.

Historically, a wide range of non-SI units were used in the United States and in Britain, but many have fallen into disuse.

This article deals only with the units commonly used or officially defined in the United States.