Design Thinking is a problem-solving process that can be applied to any business or profession to achieve extraordinary results. It is consumerized version of "User Centered Design" process that Industrial Designers were already using for many years. Recently Design Thinking is widely being marketed to teach non-designers the way designers think.
UX Process / User Centered Design (UCD)
User centered design (UCD) is a process of designing a product or service (e.g. user interface design), in which the end user is placed in the center of the process.
It helps in building easy to use(usability), efficient and delightful products.
User Interface (UI) Guidelines and Patterns
UI Guidelines/Standards is a detail documentations of UI specifications so that developers can apply these principles to create new interfaces..
UI Guidelines by its nature, is extremely detailed and complex. It is often difficult for developer to understand it. Patterns and pattern libraries are more convenient for developers because they solve common higher-level design problems without the need for deep knowledge of complex guidelines and principles. Individual UI pattern is a discrete, repeatable unit of user experience.
Interaction Design is an important part of UX umbrella. It is about making it possible for humans to interact with system in a way that is usable, desirable, and pleasurable for people. It is about connecting individual user interfaces(UI) to make a story and a meaning out of it. It uses metaphors of real world interactions into digital system to convey user mental model. To be able to design interactions you should be aware of user's goals, tasks, requirements, etc. Then understand what technology to use, what is user's psychology, environment, etc.
User research is about understanding users' needs and behavior to help product design and development process. User research is conducted at every stage of product development from concept to validating design ideas.