Much like user experience design, website design is made up of a variety of different disciplines and an expert awareness of all that is required to make a website achieve its goals.
To ensure your site looks its best there must be strength in graphic design, branding and human computer interface design. In order to ensure it is easy to use, a knowledge of web accessibility, usability and user experience design is a must. And, to ensure it can be found, understanding social media integration, search engine optimization and browser optimization, as well as competency in a range of web development programming is also crucial.
The design of any site comprises not just the look, but its simplicity of use, how it reads, how fast it runs, whether it is secure and whether it engages across a variety of platforms.