The answer is neither simple nor easy. Multimedia is the combination of computer and video technology. Multimedia really just two media sound and pictures, or in today's term, audio and video. Multimedia itself has its binary aspects. As with all modern technologies, it is made from a mix of hardware and software, machine and ideas. More importantly, you can conceptually divide technology and function of multimedia into control systems and information. The enabling force behind multimedia is digital technology. Multimedia represents the convergence of digital control and digital media---the PC as the digital control system and the digital media being today's most advanced form of audio and video storage and transmission. In fact, some people see multimedia simply as the marriage of PCs and video. PC power has reached a level close to that needed for procession television and sound data streams in real time, multimedia was born. Multimedia PC needs to be more powerful than mainstream computer---at least the multimedia PC defines the mainstream. Among contemporary PCs, about the only things that separate an ordinary computer from multimedia are a soundboard and a CD- ROM driver. The CD serves as multimedia 's chief storage and exchange medium. Without the convenient CD, the PC industry would lack a means of distributing the hundreds of megabytes of audio, visual, and textual data that make up today's multimedia titles. Without CD, you couldn't buy multimedia because publishers have no way of getting it to you.
要回答这个问题不那么容易。多媒体是计算机和视频技术的结合，实际上它是两个媒体；声音和图像，或者用现在的术语：音响和电视。多媒体本身有两个方面，和所有现代技术一样它是由硬件和软件，或机器和思想混合组成。可以将多媒体技术和功能在概念上区分为控制系统和信息。 多媒体之所以能够实现是依靠数字技术。多媒体代表数字控制和数字媒体的汇合，电脑是数字控制系统，而数字媒体是当今音频和视频最先进的存储和传播形式。事实上有人就简单地认为多媒体是电脑和电视的结合。电脑的能力达到实时处理电视和声音数据流的水平，这时多媒体就诞生了。多媒体电脑需要具有比主流电脑更强的能力，多媒体电脑决定了主流电脑的发展。区别普通电脑和多媒体电脑的主要东西是声卡和只读光盘驱动器。光盘是多媒体的主要存储和交换媒体。没有这种方便的光盘，电脑工业就无法销售构成多媒体节目的几百兆字节的音频、可视的和文字的数据，你也无法买到多媒体。 (来源：英语博客 http://space.englishcn.com)
So what is multimedia? By now you should agree that multimedia isn't any one thing but a complex entity that involves the many things: hardware, software, and the interface where they meet. But we've forgotten the most important thing that multimedia involves: you. Yeah, sure. With multimedia, you don' t have to be a passive recipient. You can control. You can interact. You can make it do what you want it to do. It means you can tailor a multimedia presentation to your own needs. You can cut through the chaff and dig directly into the important data in a report, pull together reports and video clips from around the world that interest you. That's the strength of multimedia and what distinguishes it from traditional media like books and television.
What does multimedia do? It presents information, shares ideas and elicits emotions. It enables you to see, hear, and understand the thoughts of others. In other words, it is a form of communication.