Web Design is primarily the process of planning and creating a website.
This planning and creation includes all aspects of a website such as site structure, layout, fonts, colors, user interface, information architecture and imagery.
A web design is said to be effective when all these characteristics of a website are created by keeping the principles of design in mind to meet the goals of the designer as well as the owner of the website.
Design is a major element of web design. It encompasses all facets of a website that go into making its facade such as lines, texture, shape, direction and color. However, it must be remembered that usability and utility score more over visual design when it comes to determining the success or failure of a website.