Download can be used as either a verb or a noun. As a verb, it refers to the process of receiving data over the Internet. Downloading is the opposite of uploading, or sending data to another system over the Internet. As a noun, download may refer to either a file that is retrieved from the Internet or the process of downloading a file.
Every time you use the Internet, you download data. For example, each time you visit a webpage, your computer or mobile device must download the HTML, CSS, images, and any other relevant data in order to display the page in your web browser. When you click a "Download Now" link, your browser will start downloading a specific file that you can open.
You can also download data using mediums besides the web. For example, you can download files using an FTP program, download email messages with an email client, and download software updates directly through your operating system. You can manually initiate a download (such as clicking a download link), though most downloads happen automatically. For example, your smartphone may download email messages and software updates in the background without you knowing it.
While you can download a file, the word "download" may also refer to the file itself. A common way you might see "download" used as a noun is in an online advertisement that says, "Free Download." This phrase implies that clicking the download link will download a file (often a software program or installer) and use it for free. The noun "download" can also be used like the word "transfer" to describe the process of downloading data. For example, a program may display a status update that says, "Download in progress" or "Download complete."