定义法(definition)
在科普文章的写作中，定义法是必不可少的。通过下定义，可以使读者对该事物有一个更直接的认识。
Automation refers to the introduction of electronic control and automation operation of productive machinery. It reduces the human factors, mental and physical, in production, and is designed to make possible the manufacture of more goods with fewer workers. The development of automation in American industry has been called the "Second Industrial Revolution".来源：http://www.hxen.com
这一段文字使我们了解了 "automation" 和 "Second Industrial Revolution" 两个概念，分别由 "refers to" 和 "been called" 引出。
常出现在定义法中的词语有：refer to, mean, call等。