A search engine is a software system that finds information on the World Wide Web according to a user’s textual query. The results are generally presented in a line of ranked Web pages, referred to as search engine results page (SERP). Search engines use a combination of algorithms and heuristics to prioritize relevant information and to exclude irrelevant content. In some cases, the algorithm is trained by observing human behavior and the results of searches. Search engines are designed to find specific types of information, and they vary considerably in their capabilities and functionality.

There are many techniques that can be used to improve the results returned by a search engine, and some of these involve using Boolean operators. These operators are special words that add meaning to a search string and allow it to perform more complex functions. The more effort a searcher puts into the structure of their search string, the better their results will be.

Essentially, a search engine works by first sending small programed bots out to crawl the Web. Then it systematically catalogs and stores the data collected by the bots in a repository called an index. Finally, when a person enters a query, the search engine compares the query to the index and displays the matching web pages.

Crawling: Search engine crawlers are little programs that travel to Web pages and gather all the information they can on those pages, including images, video, infographics, and articles. They are also responsible for collecting the URL of every page that they visit, so that it can be indexed and retrieved later.

Indexing: The search engine takes the pages that it has discovered and stores a record of all of the words on those pages and where they occur in each page. This is very much like the table of contents in a book. Google’s search engine has an index that contains almost everything that exists on the Internet.

Ranking: A search engine uses complex mathematical processes to organize and rank the results of a query based on a number of signals that are hidden from the public. These may include factors such as recency, interactions and the quality of a website’s content.

Adding Boolean operators to a search query can make it more powerful and accurate. For example, using parenthesis around two search terms can limit the search to that exact phrase. Alternatively, using OR combines searches that contain the same word or phrase, broadening the results. Similarly, using minus symbols, such as -jeans, can eliminate certain results that are not relevant to your query. Search engine truncation can be helpful, as it allows the searcher to specify only certain parts of a word. The default symbol for truncation is usually an asterisk, although there are many different symbols that can be used. In addition, the search engine can perform synonym searches by enclosing words in quotation marks. This helps to avoid misspellings and variation in word endings between different regions of the world.