tron

from The Collaborative International Dictionary of English v.0.48

Tron \Tron\, n.
   See 3d {Trone}, 2. [Obs. or Scot.]
   [1913 Webster]

from Jargon File (4.4.4, 14 Aug 2003)

tron
 v.

   [NRL, CMU; prob. fr. the movie Tron] To become inaccessible except via
   email or talk(1), especially when one is normally available via
   telephone or in person. Frequently used in the past tense, as in: "Ran
   seems to have tronned on us this week" or "Gee, Ran, glad you were
   able to un-tron yourself". One may also speak of tron mode; compare
   {spod}.

   Note that many dialects of BASIC have a TRON/TROFF command pair that
   enables/disables line number tracing; this has no obvious relationship
   to the slang usage.

from The Free On-line Dictionary of Computing (8 July 2008)

tron

   <jargon> ({NRL}, {CMU}, probably from the film "Tron") To
   become inaccessible except via {electronic mail} or {talk}
   especially when one is normally available via telephone or in
   person.

   Compare {spod}.

   [{Jargon File}]

   (1994-11-03)

from The Free On-line Dictionary of Computing (8 July 2008)

TRON

   1. <project> {The Real-Time Operating System Nucleus}.

   2. <language, programming, testing, tool> (TRace ON) A
   {command} used when {debugging} {programs} written in
   early {line-numbered} {BASIC} that contained {GOTO} and
   {GOSUB} statements.

   When the TRON command had been {executed}, the program ran
   with a {window} open indicating the line number being
   executed at that instant.

   The {TROFF} (an abbreviation for "TRace OFF") command turned
   the {tracing} off.

   (2003-02-02)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

TRON
       The Realtime Operating system Nucleus