Keyword search is a method used to find specific information in databases, search engines, or websites by entering particular words or phrases. These keywords help the system identify relevant content, making it easier for users to locate the information they need quickly. When a user types in a keyword, the search engine scans its indexed data to retrieve results that match or relate to those terms. This process is essential for effective online research, as it narrows down vast amounts of information to a more manageable set of results, enhancing the overall search experience.