TNHD meaning in Computing ?

The Jargon File is a glossary and usage dictionary of slang used by computer programmers. The original Jargon File was a collection of terms from technical cultures such as the MIT AI Lab, the Stanford AI Lab (SAIL) and others of the old ARPANET AI/LISP/PDP-10 communities, including Bolt, Beranek and Newman, Carnegie Mellon University, and Worcester Polytechnic Institute. It was published in paperback form in 1983 as The Hacker's Dictionary (edited by Guy Steele), revised in 1991 as The New Hacker's Dictionary (ed. Eric S. Raymond; third edition published 1996).

The concept of the file began with the Tech Model Railroad Club (TMRC) that came out of early TX-0 and PDP-1 hackers in the 1950s, where the term hacker emerged and the ethic, philosophies and some of the nomenclature emerged.