跨平台泛指编程语言、软件或硬件设备可以在多种操作系统或不同硬件架构的电脑上运作。

指支持多种操作系统的软件。

大部分计算机语言从绝对意义而言，都是跨平台的：因为都是以高级的、人类可读的方式来对CPU发号指令，这样也就没必要依赖于任何操作系统。但如果要用系统的部件工具箱，来新建用户图形界面（GUI），就可能会用到开发员特定系统中的API函数或库类。虽然C++是跨平台的，但Windows下用到Win32 API的C++进程，一般就不能在Unix机器上编译。不同编译器对语言规范的解释也有所差异。这样的话，在针对不同系统进行构建之前，进程就得加以考虑。

In computing, cross-platform, multi-platform, or platform independent, is an attribute conferred to computer software or computing methods and concepts that are implemented and inter-operate on multiple computing platforms. Cross-platform software may be divided into two types; one requires individual building or compilation for each platform that it supports, and the other one can be directly run on any platform without special preparation, e.g., software written in an interpreted language or pre-compiled portable bytecode for which the interpreters or run-time packages are common or standard components of all platforms.