Web development is a service that involves the creation, maintenance, and improvement of websites. It encompasses a wide range of tasks and technologies, including designing and coding website layouts, developing and integrating features such as forms, search functionality, and e-commerce capabilities, and ensuring that websites are mobile-friendly and accessible to all users. 

Web development services can be provided by individuals or agencies, and can range from simple website updates to the full development of complex, dynamic web applications. The goal of web development is to create a website that is visually appealing, easy to navigate, and optimized for search engines, all while meeting the specific needs and goals of the client.