The phrase "app side" refers to something that is related to or part of an application, specifically focusing on the software or program aspect of it. Full definition
That's not to say the Pixel C is a perfect device, but at least you can now run apps side by side with the latest Android N developer preview. (techspot.com)
I've grown used to running apps side - by - side when drafting articles on my phone, where I normally write in one window and reference from another. (thenextweb.com)
The device will also feature multitasking that allows the user to snap apps side by side just like you would expect to be able to do on a dual - screen device. (windowscentral.com)