A turn in basketball is an offensive staple that can be used in a few different contexts. The offensive player will rotate themselves towards the rim or turn towards the basket to face it as opposed to their previous backwards facing position. This could be done in order to create some space for a jump shot, to better see others on the court for a pass, as a direct segway to a drive and post move depending on the location on the court, and finally as a previous move to a step back or fade away.
As described before, there are a multitude of offensive options that involve the basic move of turning to face the rim. Any of these options could be used depending on the player and what the defense is also doing. The turn could be incorporated into the offense in a way such as a player catches the ball in a post-up position then turns around to face the rim before making another decision about what to do with the ball.
The turn can be a simple yet dangerous move if used effectively by the offense so the defense must be careful and watch for it. A good offensive player could also turn straight around a defender for an open drive or shot so if an offensive player is able to use a turn, the defense must keep them in front. This will limit the offensive options especially if they cannot shoot well. By forcing another pass the defense is able to neutralize the immediate effect of the turn and stop it from creating good scoring chances.