Design Thinking is a term used to articulate an approach to solving (complex) challenges, based on the way designers work. It differs from other problem-solving approaches by fundamentally being context- and human-centred, meaning solutions and services from design thinking processes have people as a focal point (i.e. citizens, users, customers). The stakeholders can be involved in various ways, from informants to co-creators to testers etc. 

Combined with this central human role is also a mix of technology assessment (feasibility) as well as business success requirements (viability). Ultimately, the main focus of Design Thinking is therefore on humans and on co-creation of a product that is grounded in research-based arguments, prototypes and iterative processes

It is worth noting it rather describes a way of working or a mentality, than a concrete method or even a holistic methodology. Design Thinking is thus more to be understood as a mindset, rather than a set of specific tools. It therefore draws equally on specific tools and methods from e.g. UX design, Interaction design, Participatory design as well as business development and agile work methods.