What is the meaning of the PI function. I am solving for a configuration problem and i have seen a function π  
This is a function not 3.14 which is the value of pi. While accessing some lectures i found out that they also call this symbol as product of something. I don't have much to show for it but here's the symbol .



Please lead me to some resource.
Maybe it's the product function $\Pi_{i=0}^{n}x_i\equiv x_0 \cdot x_1 \cdot \ldots \cdot x_n$. See https://en.wikipedia.org/wiki/Product_(mathematics)

There's also the number theory use, where $\pi(x)$ is the number of primes less than or equal to $x$. See https://en.wikipedia.org/wiki/Prime-counting_function
As most of us know, Pi is defined as the ratio of a circle’s diameter to its circumference. As a retired engineer, l still have it memorized to 7 decimal points, ie 3.1415926. It is called a transcendental number, or function, because using finite math it Never divides out. In (about) 1990, MIT used a Cray supercomputer to see if the machine could finish in a day. It could not... even after 10e670,000,000,000+/- permutations. (l honestly don’t remember how many orders of magnitude it ran but it certainly convinced me.) The most recent and accurate attempt was In 2014: the world record was a computer that calculated Pi (π) correctly to 13,300,000,000,000 decimal places.
Many mathematicians now call it an “indefinite finite” function, or an “irrational” number, but to me it is asymptotic. Ask your pc to find sq rt 145 and you will see similar results. There are lots of them out there.  Fortran (or formula translation) language run on a mainframe will generally throw you out after 10e7 with an error code saying Excceeds Maximum Allowed Permutations.
For the record, the formula used for calculating pi is:
Gregory-Leibniz Series:
\frac{\pi}{4}=1-\frac{1}{3}+\frac{1}{5}-\frac{1}{7}+\frac{1}{9}-\ldots.  Written non-code: pi/4=1-1/3+1/5-1/7+1/9-...  Notice the denominators are prime numbers.
Where frac = fraction
And ldots   = ellipsis (continue series - ...)
If one uses this method he or she will quickly substitute ldots with lDIOTS for it’s tedious nature is... Tedious    :-)
There are about five accepted formulas but l consider the G-L series the most fundamentally beautiful.  Hope this helped.