ya u r right.. there is no term robot its robot .txt file which tell spider wht to crawl and wht not..........
Robots.txt is a text (not html) file.Robot is the spider who come to all website to collect the data for searches.You can get detailed explanation of robot.txt at http://www.robotstxt.org/robotstxt.html.
the actual term is robot.txt file which tells the spider which page to be crawled and which not????????