Download, Sideload, and Upload

Many get these confused, but is easy to tell the difference once you understand.

The term "sideloading" is very similar to the more common terms "downloading" and "uploading," and it is much easier to understand what sideloading means if you are already familiar with those terms. Sideloading does not make use of the internet, it requires you to use some other method to transfer files. This can be accomplished with a physical connection between the two devices, like a USB cable, or via a wireless method like Bluetooth or Wi-Fi. If the mobile device has a memory card slot, sideloading can also involve copying files from a computer to an SD card and then inserting the card into the mobile device.

Downloading involves transferring a file from a remote location, like the internet, to a local device like your computer. Uploading is the opposite, since it involves transferring a file from a local device, like your computer, to a remote location like a file hosting service on the internet.

Bottom line, Think of the internet as a cloud. You upload to the cloud and you download from the cloud. Think of another device sitting beside yours. You sideload from it.