A project is a collection of connected data nodes in TIS Editor. See TIS Project.
Solution
A solution is a set of projects or a single project that aims at providing a complete functionality to users. E.g. the "Forecasting" Solution consists of several projects.
A small window that can contain data, text, visualizations or allows for interaction and provides many useful features (e.g., updating, paging, …) E.g. a Simple Grid Portlet
A page is an element of TIS Board that contains zero or more portlets.
Pages are displayed and organized as tabs, similar to the tabs of a web browser. Note, that there is a limit on the number of opened pages (defined in the settings by the administrator).