Discover- The is the start of design thinking where user needs are identified. It includes market research and user research.
Define- In this stage the problem id identified and defined from research and the potential solution aligned with business goals. This consist of project development and management.
Develop- In this stage the design team creates solutions that are iterated and tested through until they match the specification or brief. It includes prototyping, user testing, feedback and iterative looping.
Deliver- Finally the product or service gets delivered to the market and gets publicly launched. This stage consists of approval, launch and evaluation.