from
Jargon File (4.4.4, 14 Aug 2003)
backbone site
n.,obs.
Formerly, a key Usenet and email site, one that processes a large
amount of third-party traffic, especially if it is the home site of
any of the regional coordinators for the Usenet maps. Notable backbone
sites as of early 1993, when this sense of the term was beginning to
pass out of general use due to wide availability of cheap Internet
connections, included uunet and the mail machines at Rutgers
University, UC Berkeley, {DEC}'s Western Research Laboratories, Ohio
State University, and the University of Texas. Compare {leaf site}.
[2001 update: This term has passed into history. The UUCP network
world that gave it meaning is gone; everyone is on the Internet now
and network traffic is distributed in very different patterns. Today
one might see references to a "backbone router" instead --ESR]