HPC stands for High Performance Computing.

High performance computing is an area of computer-aided computing. It includes all computing work that requires a high level of computing power or storage capacity.

Due to the rapid development of computing technology, there are no permanent formal criteria for the exact delimitation of high-performance computing from the other areas of computer-aided computing. However, it is generally recognized that computing applications, the complexity or size of which makes computation on simple workstation computers impossible or at least nonsensical, fall into the field of high-performance computing.

High-performance computing is primarily made possible in the first place by the architecture of high-performance computers, which is geared towards parallel processing. In order for applications to be able to use this architecture, they must be programmed in parallel. This can be done with OpenMP and MPI, for example.

from Wikipedia