A selection-based search system is a search engine system in which the user invokes a search query using only the mouse. A selection-based search system allows the user to search the internet for more information about any keyword or phrase contained within a document or webpage in any software application on their desktop computer using the mouse. Traditional browser-based search systems require the user to launch a web browser, navigate to a search page, type or paste a query into a search box, review a list of results, and click a hyperlink to view these results. Three characteristic features of a selection-based search system are that the user can invoke search using only their mouse from within the context of any application on their desktop (for example Microsoft Office, Adobe Reader, Mozilla Firefox, etc.), receive categorized suggestions which are based on the context of the user-selected text (or in some cases the wisdom of crowds), and view the results in floating information boxes which can be sized, shared, docked, closed and stacked on top of the document that has the user’s primary focus. In its simplest form, selection-based search enables users to launch a search query by selecting text on any application on their desktop. It is commonly believed that selection-based search lowers the user barrier to search and permits an incremental number of searches per user per day. Selection-based search systems also operate on the premise that users value information in context. They may save the user from having to juggle multiple applications, multiple web browsers or use multiple search engines separately. The term selection-based search is frequently used to classify a set of search engine systems, including a desktop client and a series of cloud computing services, but is also used to describe the paradigm of categorizing a keyword and searching multiple data sources using only the mouse. The National Information Standards Organization (NISO) uses the terms selection-based search and mouse-based search interchangeably to describe this web search paradigm. (en)