Verilog and Verilog HDL (Hardware Description Language) are essentially the same thing. Verilog is a hardware description language used in electronic design automation, and “HDL” simply stands for “Hardware Description Language.” Therefore, when people refer to “Verilog,” they are often referring to Verilog HDL.
However, to clarify any potential confusion, sometimes “Verilog” may be used in a broader sense to refer to the entire ecosystem surrounding the language, including various versions, extensions, and tools associated with it. In this context, “Verilog” could encompass not only the language syntax but also its implementation, simulation tools, and related methodologies used in digital design. Nonetheless, in most cases, “Verilog” and “Verilog HDL” are used interchangeably to denote the hardware description language itself.