A sitemap is a diagrammatic representation of a hierarchical system. It usually depicts the parent-sibling relationship between pages in a website, showing how sub pages might be arranged underneath their parent groupings. This arrangement forms a map of the site.
A user journey represents a sequence of events or experiences a user might encounter while using a product or service. A user journey can be mapped or designed to show the steps and choices presented as interactions, and the resulting actions.
A prototype is draft representation built to test ideas for layout, behaviour and flow in a system. Prototypes are an indispensable tool for resolving a large number of potential issues in a concept or business before too many resources are deployed to put a design into production.
A Wireframe is a visual schematic that conveys a basic level of communication, structure and behaviour during the design of a system. Wireframes are low-fidelity designs that bypass including a detailed user interface or visual design, conveying just enough to get across the core idea.
To say something is usable is a qualitative statement about how easy that thing is to use. Usability is an assessment of how learnable a system is and how easy a user finds it to use. The usability of a system or product is a key factor in determining whether the user experience is a good one.
Information architecture is the design and organisation of content, pages and data into a structure that aids users understanding of a system. A more organised system enables users to more easily find the information they require and complete the intended tasks.
User Interface Design is the discipline of designing software interfaces for devices, ideally with a focus on maximising efficiency, responsiveness and aesthetics to foster a good user experience.
The practice of User Experience (UX) Design is the coming together of many specific design related disciplines to improve the usability, responsiveness, uptake and aesthetics of a product or service.
A general term that covers all aspects of a user's participation while engaging with something that has been designed. Usually when talking about User Experience in the digital design field it refers to the interactions, reactions, emotions and perceptions while using an app, service, website or product.