Definition or define, depending on which sort of piece of history you come from.

也就是定义或者解释,取决于你来源于那段操作历史。

麻省理工公开课 - 计算机科学及编程导论课程节选

Now, in the world of Linux and Unix more generally, both of which are our operating systems that had been around for many, many years, Mac OS is based on one of-- one version thereof.

在Linux和Unix里更广泛，对了，这两个都是历史悠久的,操作系统，就连Mac操作系统,都是基于它的一个版本设计出来的。

哈佛公开课 - 计算机科学课程节选