VHDL, or VHSIC Hardware Description Language, is a hardware description language used in electronic design automation (EDA). It allows designers to create models of digital systems, such as integrated circuits, in a text-based format. These models can be used to simulate the behavior of the systems they represent before they are built. VHDL was developed in the early 1980s when there was a need for a standard hardware description language. The language was initially based on the Ada programming language but has evolved over time to include features from other languages, such as Verilog HDL and SystemVerilog. VHDL is widely used in the electronics industry and is one of the two languages approved by the International Organization for Standardization (ISO) for describing digital circuits. It is also a popular teaching tool, due to its readability and comprehensibility.