Fathom

The name 'fathom' was derived from the Old English verb fæðm, meaning to embrace.

It was originally used to measure distance on land, but by the end of the seventeenth century it was generally used to measure the depth of water.

By the early nineteenth century, the length of a fathom was set at six feet (1. 828 meters). However, in the mid-decades of the eighteenth century a fathom containing six feet was used by the Royal Navy, while merchant ships employed a measurement of five and a half feet called the middling fathom. Also, the crew of smaller boats with shallower draughts, such as fishing vessels, used a measurement called the small fathom, which contained five feet.

The Admiralty abandoned the fathom as a standard unit of measurement in favour of the meter in 1968.