/I-R-C/ [Internet Relay Chat] n. A world-wide "party line" network that allows one to converse with others in real time. IRC is structured as a network of Internet servers, each of which accepts connections from client programs, one per user. The IRC community and the USENET and MUD communities overlap to some extent, including both hackers and regular folks who have discovered the wonders of computer networks. Some USENET jargon has been adopted on IRC, as have some conventions such as emoticons. There is also a vigorous native jargon, represented in this lexicon by entries marked `[IRC]'. See also talk mode. iron n. Hardware, especially older and larger hardware of mainframe class with big metal cabinets housing relatively low-density electronics (but the term is also used of modern supercomputers). Often in the phrase big iron. Oppose silicon. See also dinosaur.