CHANNEL MODE o

Usage: MODE <channel> +|-o [<nick>]
o - Channel operator
Gives the user whose nickname immediately follows the +o operator status in the channel. Channel operators are able to set the configuration of a channel with the exception of a very small quantity of server operator modes.
Privilege: channel operator
Examples:
/mode #movies +o moonman

CHANNEL MODE O

Usage: MODE <channel> +|-O [<channel>]
O - Overflow
If you set a user limit in the channel and have mode +O on, it will redirect the users in the second channel. To use this mode you must set the channel +l (limit), when the limit is reached the next user to join will be sent to the specified overflow channel.
Privilege: channel operator
Examples:
/mode #movies +O
See also: CMODE +l