Asset

In Craft CMS, an Asset is a rep­re­sen­ta­tion of an uploaded file, like images, videos, doc­u­ments, PDFs, or any oth­er dig­i­tal file you might need for your website. 

The file lives on a serv­er an Asset is an Ele­ment Type, just like entries, cat­e­gories, or users. This means you can do things like can attach meta­da­ta to each Asset through cus­tom fields.