BUILT-IN MATHEMATICA SYMBOL

Remove

Remove[symbol₁, ...]
removes symbols completely, so that their names are no longer recognized by Mathematica.

Remove["form₁", "form₂", ...]
removes all symbols whose names match any of the string patterns .

Details Details

You can use Remove to get rid of symbols that you do not need, and which may shadow symbols in contexts later on your context path.
Remove["form"] allows the following metacharacters:
* match zero or more characters

@ match one or more characters, but not uppercase letters
Remove["context`*"] removes all symbols in a particular context.
Remove is HoldAll.
Remove does not affect symbols with the attribute Protected.
Once you have removed a symbol, you will never be able to refer to it again, unless you recreate it.
If you have an expression that contains a symbol which you remove, the removed symbol will be printed as , where its name is given in a string.