From Environment Variables
Path environment variable returns an ordered list of folders that will be searched when the OS is requested to execute an application that includes no specific path in the filespec. Several folders may be specified in the path, separated by semicolons (;).
In order to find executable modules and its dependencies, Windows operating system uses Path and PathExt environment variables. It searches through directories listed in Path and tries to find an executable module with one of the extensions specified in PathExt. Order in which items are listed is important. The first match found will be used. Windows allows to define both system global and user specific path settings. The end result is a concatenation of these two variables where system value comes first before the user value.
echo %Path% C:\Windows\system32;C:\Windows;...
Path environment variable doesn't have default value.
AllUsersProfile | AppData | CD | ClientName | CmdCmdLine | CmdExtVersion | ComSpec | CommonProgramFiles | ComputerName | Date | ErrorLevel | HomeDrive | HomePath | LocalAppData | LogonServer | Number Of Processors | OS | Path | PathExt | Processor Architecture | Processor Identifier | Processor Level | Processor Revision | ProgramFiles | Prompt | Random | SessionName | SystemDrive | SystemRoot | Temp | Time | Tmp | UserDnsDomain | UserDomain | UserName | UserProfile | WinDir