8.5 Session Name

Command: sessionname [name]

(none)
Rename the current session. Note that for screen -list the name shows up with the process-id prepended. If the argument name is omitted, the name of this session is displayed.
Caution: The $STY environment variable will still reflect the old name in pre-existing shells. This may result in confusion. Use of this command is generally discouraged. Use the -S command-line option if you want to name a new session.The default is constructed from the tty and host names.