Waterfall is a method of building software where each phase of development is completed and fixed, before sequentially moving on to the next.
A white label solution is a product that offers functionality off the shelf and can be procured by other companies so that they don’t need to build a bespoke solution. The solution can usually be customised to suit a particular customer journey or functionality and can often be be embedded seamlessly into a customers existing product.
Wireframe is a draft of the layout of a page or software that's being built. It helps Designers visualise how elements are distributed in order to provide the best user experience.