RNG stands for Random Number Generator. It is a mathematical system, algorithm, or device that generates a sequence of numbers that are not predictable and lack any pattern, giving the appearance of randomness.
In the context of slot machines, both physical and online, an RNG is used to determine the outcome of each spin. The moment you press the 'spin' button or pull the lever, the RNG generates a random number that decides which symbols the reels will land on.
RNGs are a crucial component of fair and unbiased gaming. They ensure that each spin's outcome is entirely independent of the previous or next spin, making it impossible to predict or manipulate the result. This is why every spin of the slot machine, no matter the previous outcome or the time between spins, has an equal chance of winning or losing.
For fairness and transparency, RNGs in licensed and regulated casinos or game developers are often tested and certified by independent third-party auditors to ensure they operate correctly and produce truly random results.