texmf
as the name of the root directory
(folder) of the hierarchies. Files supplied as part of the
distribution are put into the standard hierarchy. The location of the
standard hierarchy is system dependent, but on a Unix system it might
be at
/usr/local/texmf, or
/usr/local/share/texmf, or
/opt/texmf, or
a similar location, but in each case the TeX files will be under the
/texmf subdirectory.
There may be more than on ‘local’ hierarchy in which additional files
can be stored. In the extreme an installation can have a local
hierarchy and each user can also have an individual local hierarchy. The
location of any local hierarchy is not only system dependent but also user
dependent. Again, though, all files should be put under a local /texmf
directory.
The TDS is published as the output of a TUG
Technical Working Group.
You may browse an on-line version of the
standard, and copies in several other formats (including source) are
available on CTAN.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=tds