Hard IP (FPGA)
Beginner
Parts of an FPGA that come already built, like fast links or a small processor, instead of being made from the general blocks.
Novice
Fixed circuits built into an FPGA for common, demanding jobs: high-speed transceivers, PCIe interfaces, memory controllers and processor cores. They are smaller, faster and lower power than the same thing in programmable logic.
Expert
Fixed-function silicon placed in the fabric (SerDes, PCIe, DDR controllers, Arm or RISC-V subsystems). It narrows the gap to an ASIC for the functions it covers and is dead area for designs that don’t use it.
Explained in Lookup tables and the FPGA fabric (Architectures).
See also: Block RAM (BRAM), DSP block, SoC.