Tk

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

Tk

   <programming, graphics> A {GUI} library, generally used with
   {TCL} by {John Ousterhout}, but also available from within {C}
   or {Perl}.  Tk is available for {X Window System}, {Microsoft
   Windows} and {Macintosh}.  Tk looks very similar to {Motif}.

   Version 3.5.

   (ftp://ftp.cs.berkeley.edu/ucb/tcl/).

   (1995-11-09)

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

tk

   <networking> The {country code} for Tokelau.

   (1999-01-27)

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

TK
       TeleKommunikation

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

TK
       Temporal Key (FPK)