The fathom equals exactly 6 feet or 1.8288 meters. It is the traditional marine unit for water depth, used on older nautical charts and in recreational sailing. Modern charts mark depths in metres, but fathoms still appear in maritime literature and older US charts.
Real-world: A "mark twain" reading — made famous by the Mississippi riverboats — meant 2 fathoms (3.66 m) of water, the minimum safe depth.
Read full fathom reference →The meter is the base SI unit of length. It was first defined in 1793 as one ten-millionth of the distance from the equator to the North Pole through Paris. Today it is defined as the distance light travels in vacuum in 1/299,792,458 of a second — a definition tied directly to the universal speed of light. The meter is the foundation of the metric system used by 95% of the world.
Real-world: A standard door is about 2 metres tall. An Olympic swimming pool is exactly 50 metres long. The Eiffel Tower is 330 metres tall.
Read full meter reference →