Bot (robot, spider, crawler)
A bot is a software application or script which is programmed to carry out a series of tasks automatically over the internet. The most common example are bots created by search engines that crawl websites on the world wide web, fetching and indexing the content on web pages. Another type of bot is a chat bot which is employed by companies to answer customer service questions. There are also bots which are created for malicious purposes like carrying out DDOS attacks which bombard web servers with communication with the aim of preventing them from handling legitimate web traffic.