Cutoff

(CO)
positions

The position one seat right of the button. Second-best position.

From the CO you act before the BTN but still in late position vs the blinds. Open ranges from CO are roughly 25–30% in modern 6-max.

See also

Big Blind (BB)
The forced bet posted by the player two seats left of the dealer.
Dealer Button
The best position — last to act on every postflop street.
Position
Where you sit relative to the dealer button. Later = better.
Small Blind
The smaller forced bet posted by the player left of the dealer.