A TRNG (True Random Number Generator) is hardware that uses nondeterministic physical processes to randomly generate numbers.
A TRNG (True Random Number Generator) is hardware that exploits non-deterministic physical processes to generate random numbers. The output may be of any distribution and the distribution is not guaranteed to be random, so output cannot be used as-is and whitening is often necessary.
People who misunderstand randomness and probability theory often believe that TRNGs are required for security. In reality, TRNGs are typically only required on systems that do not have any source of inputs where entropy can be collected, such as embedded systems or servers. On all other systems, unpredictable events such as interrupts can be used to seed a CSPRNG instead.