A fathom is a unit of length in the imperial and the U.S. customary systems equal to 6 feet (1.8288 m), used especially for measuring the depth of water. ... Historically, however, it is the most frequently employed maritime measure of depth in the English-speaking world.

What is a fathom and what is it used for?

fathom, old English measure of length, now standardized at 6 feet (1.83 metre), which has long been used as a nautical unit of depth.

What is fathom depth of water?

A fathom is a nautical unit of measurement and is equal to six feet . On a chart, water depths may be connected with a line known as a depth contour, similar to the topographic lines or surface features that you see on a map.