Definition - What does Cross-Browser mean?
Cross-browser refers to the ability of a website, HTML construct, application or even client-side script to work in several different environments, ones that provide its required features. Similar to the way a cross-platform program is one that can run across multiple computer platforms, cross-browser websites are capable of running in several browsers.
Techopedia explains Cross-Browser
One way of ensuring compatibility is to use a basic coding method that weeds out incompatibilities between different browsers. However, if this is not possible, then a developer must customize the code accordingly. Cross-browser compatibility is very important for smooth functioning of web applications.