$TopDirectory (Obsolete Mathematica Symbol)

Since Version 5.0 (released in 2003), $TopDirectory has been superseded by $InstallationDirectory and $BaseDirectory.

$UserAddOnsDirectory (Obsolete Mathematica Symbol)

Since Version 5 (released in 2003), $UserAddOnsDirectory has been superseded by $UserBaseDirectory.

$$Media (Obsolete Mathematica Symbol)

Since Version 2.0 (released in 1991), $$Media has been superseded by Streams.