Fathom
Fathom was originally a land measuring term derived from the Anglo-Saxon word "fætm" meaning literally the embracing arms, or to embrace. In those days, most measurements were based on average sizes of parts of the body, such as the hand or foot, or were derived from average length between two points on the body. A fathom is the average distance from middle-fingertip to middle-fingertip of the outstretched arms of a six-foot tall man. Even today in our modern Navy, Sailors can be seen "guesstimating" the length of line by using the Anglo-Saxon fingertip method; crude but still reliable.