Angular velocity ω is a has magnitude and direction.  Its magnitude is the angular speed, and its direction is the direction of the axis of rotation. 
To specify the sense of rotation we use a convention called the right-hand rule.  If the fingers of your right hand are curling to indicate which way the wheel is turning, then the thumb of you right hand is pointing in the direction of the axis of rotation.  This is the direction of the angular velocity.
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