1. Internet Relay Chat, a protocol for instant communication via the Internet
2. Internal Revenue Code

Verb

1. To participate in IRC (Internet Relay Chat).
   • 1995, Stuart Harris, The Irc Survival Guide

     <- irced 2 yrs without aliases ...

   • 2002, James Arnt Aune, Selling the Free Market

     ...IRCing can confirm the observation that work and play appear to constitute a continuum for the digerati.

   • 2004, Allison Rushby, Friday Night Cocktails

     ...not that this is strange or anything, I do the same thing myself when I'm IRCing — there're some real weirdos out there roaming the Net...