Cross-platform (a.k.a. agnostic, agnostic application, and agnostic platform) refers to something that is interoperable among different operating systems, systems, and platforms. Cross-platform, however, is more focused on software that can run on any operating system and on any processor architecture.
Why is it Important to the IT Professional?
As an IT professional, you want something that you could use on any computer anywhere. As a software developer, you want to have as many potential users as possible. But this is becoming very pronounced now as more and more devices become available. Moreover, there are a variety of operating systems for each of these devices. Coming up with a Cross-platform software ensures your dominance in your field. Take for example Firefox. Mozilla has poured a lot of hours into making sure that Firefox works on PCs, Macs, Linux machines, and iOS and Android devices. What this means is that a lot more of their users are using Firefox and keeping their devotion to the browser. This leaves no leeway for the competition to get into the picture.