Whats is attributes in Visualforce page tags in Salesforce ?

Apart from standard Visualforce markup, the body of an <apex:component> tag can also specify the attributes that can be passed in to the custom component when it’s used in a Visualforce page. The values of such attributes can then be used directly in the component, or within the component’s controller, if applicable. They can’t, however, be used in the constructor of the component’s controller.