Great Renaming n.
The flag day in 1987 on which
all of the non-local groups on the Usenet had their names changed from the net.-
format to the current multiple-hierarchies scheme. Used esp. in
discussing the history of newsgroup names. "The oldest sources
group is _comp.sources.misc_; before the Great Renaming, it
was _net.sources_." There is a Great Renaming
FAQ on the Web.