Random number is a number that is chosen from a pool of numbers in a way that the next number chosen from the pool is not predictable.
There is a philosophical question as to what “random” actually is, but its definition is absolute. If the sequence of numbers is random,
you should not be able to predict the next number in the sequence without knowing the part of the sequence so far.
Random number generators can be hardware based or pseudo-random number generators. Hardware based random-number generators can involve
the use of a dice, a coin for flipping, or many other devices.
A pseudorandom number generator (PRNG), also known as a deterministic random bit generator (DRBG), is an algorithm for generating a sequence
of numbers whose properties approximate the properties of sequences of random numbers. The PRNG-generated sequence is not truly random, because
it is completely determined by an initial value, called the PRNG's seed (which may include truly random values).
(Source :- Wikipedia)