Databases are a very important tool for research. They have a lot of information, it's arranged with research in mind, and the sources are reliable. You search a database by topics and keywords -- like searching #hashtags on Instagram. You can limit your results by publication date, type of information, and reading level -- like shopping online and limiting the results to a certain size or price.
A database is any organized collection of information. Usually, when we talk about databases in the library, we are talking about collections of scholarly and professional articles, periodicals, primary source documents, etc... But really, a database can contain any kind of data, such as text, video, images, or sound files.
While Google is an amazing tool that is very easy to use, using scholarly databases to do research for schoolwork or other important projects will ensure that your sources of information come from reputable sources. Additionally, because these databases are made specifically for doing research, there are tools such as topic finder, subject search, and a variety of filters that will help lead you to the information you need.
Why do I need to know all this stuff about databases when I can just find stuff online? This video will explain some of the reasons why using the library's resources, including databases, will usually provide higher quality information than searching the wild internet.