Fathom to the Old High German word "fadum" meaning embracing arms or a pair of outstretched arms. In Middle English it was "fathme". The Ancient Greek measure known as the orguia (, "orgyiá", "outstretched") is usually translated as "fathom". By the Byzantine period, this unit came in two forms: a "simple orguia" (, "haplē orguiá") roughly equivalent to the old Greek fathom (6 Byzantine feet, m) and an "imperial" (, "basilikē") or "geometric orguia" (, "geōmetrikē orguiá") that was one-eighth longer (6 feet and a span, m). One fathom is equal to: In the international yard and pound agreement of 1959
Fathom more variable: from feet on merchant vessels to either on fishing vessels (from ). At one time, a quarter meant one-fourth of a fathom. A cable length, based on the length of a ship's cable, has been variously reckoned as equal to 100 or 120 fathoms. Most modern nautical charts indicate depth in metres. However, the U.S. Hydrographic Office uses feet and fathoms. A nautical chart will always explicitly indicate the units of depth used. To measure the depth of shallow waters, boatmen used a sounding line containing fathom points, some marked and others in between, called "deeps", unmarked but