The point is a unit of length in the field of typography and uses the symbol pt.
It is the smallest unit in the world of typography. There are 12 points in a pica.
In physical printing methods / press systems, the point size is the height of the metal press body on which the font's letters are made. When applied to the digital type space, letters are designed around a theoretical size, an em square which is scaled to the relative point size (when specified of course!).
The fathom is a unit of length in the imperial unit system and uses the symbol ftm.
One fathom is equal to 6 feet or 1.8288m.
The phrase fathom derives from an old English derivative of a Viking / Danish word "favn" meaning emracing a pair of arms or a pair of oustretched hands.
The fathom is mostly used in the nautical world to describe depths of water.