Search engine indexing is the process of collecting, parsing, and storing data to enable fast and accurate information retrieval. The design of an index incorporates interdisciplinary concepts from linguistics, cognitive psychology, mathematics, informatics, and computer science. Web indexing is an alternate name for this process in the context of search engines designed to find web pages on the Internet. Popular search engines focus on full-text indexing of online natural language documents. In addition to text-based documents, media types such as pictures, video, audio, and graphics are also searchable.