Keywords are those specific words which are searched in a search engine. When you search any information on the web in any order, you open a search engine and write some keyword describing what you are looking for. At the other end, the search engine checks your desired keyword related information in its database and shows the results listing pages according to the words submitted. These words that are used to search anything called keywords or search terms. If you have used some search terms, you will know that even a single keyword shows a broad list of required information.