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 parsec is a unit of length and is used in the Astronomical system of units. It is denoted by the symbol pc.
It is equal to 3.26156 ly (light years) which is approximately 31 trillion kilometres (19 trillion miles). It's used to measure huge distances to objects and planets outside of our Solar System.
It was first brought into use by Herbert Hall Turner (a British Astronomer) in 1913 and was invented to use in calculations of astronomical distances to make it easier in calculations using raw data.