In Bootstrap, a component may be used regardless of the other components and its default style is already defined inside the main Bootstrap CSS (though a few may also require JavaScript). Thus, you can generate as many different instances of a component as per your requirements with the same visual style applied to them and saving yourself precious time and effort, thereby allowing you to focus on the more vital parts of your development process.
Glyphicons is a utility of monochromatic icons and symbols with emphasis on simplicity, keeping usability in mind. The creators of Glyphicons have provided these icons free of cost for Bootstrap. The official Glyphicons web page at http://glyphicons.com/ contains a detailed list of all the icons that are of great use while developing complex websites, as icons are better than words in most cases.
The following screenshot displays some of the popular Glyphicons available for Bootstrap:
Take a look at the following...