A field-programmable gate array (FPGA) is a type of integrated circuit that can be configured, and reconfigured, after it is manufactured. Instead of having fixed circuitry, it contains a grid of programmable logic blocks and interconnects that engineers wire together, usually by writing a design in a hardware description language such as VHDL or Verilog, so the chip performs a specific digital function.
Because they can be reprogrammed and process many operations in parallel, FPGAs are widely used for prototyping custom chips, low-volume products, telecommunications, automotive, aerospace and industrial equipment. Xilinx, now owned by AMD, released the first commercially viable FPGA, the XC2064, in 1985; Altera is the other long-standing major maker.
Source: Wikipedia: Field-programmable gate array
Image: Altera Stratix IV GX FPGA by Altera Corporation, CC BY 3.0, via Wikimedia Commons.