The word netlist can be used in several different contexts, but perhaps the most popular is in the field of electronic design. In this context, a "netlist" describes the connectivity of an electronic design.
Netlists usually convey connectivity information and provide nothing more than instances, nets, and perhaps some attributes. If they express much more than this, they are usually considered to be a hardware description language such as Verilog, VHDL, or any one of several specific languages designed for input to simulators.
Netlists can be either physical or logical; either instance-based or net-based; and flat or hierarchical. The latter can be either folded or unfolded.
Read more about Netlist: Contents and Structure of A Netlist, Hierarchy