Small Blind

(SB)
positions

The smaller forced bet posted by the player left of the dealer.

Worst position postflop, must act first against the BB. SB defends are wider than BB defends in modern theory because of pot odds.

See also

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