Web design is the process of planning, creating, and maintaining websites.
Web development is the process of building and maintaining websites and web applications.
SEO is the practice of optimizing websites to improve their visibility and ranking on search engines.
Ecommerce (electronic commerce) refers to the buying and selling of goods or services over the internet.
App development is the process of creating software for mobile devices, tablets, or the web.
DevOps is a set of practices that combines software development (Dev) and IT operations (Ops).