Dictionary.net

To surround a section of code with commentdelimiters or to prefix every line in the section with acomment marker. This prevents it from being compiled orinterpreted. It is often done to temporarily disable thecode, e.g. during debugging or when the code is redundant orobsolete, but is being left in the source to make the intentof the active code clearer.The word "comment" is sometimes replaced with whateversyntax is used to mark comments in the language in question,e.g. "hash out" (shell script, Perl), "REM out" (BASIC),etc.Compare condition out.