How is TAS affected by wind?
Correct.  True airspeed refers to the actual speed which the aircraft is moving through the air.  Ground speed is the speed at which the aircraft moves over the ground.  The formula

$v_\text{ground} = v_\text{true} - v_\text{wind} \cdot \cos(\alpha)$

Where  


$v_\text{true}$ is the true airspeed
$v_\text{ground}$ is the groundspeed
$v_\text{wind}$ is the magnitude of the winds aloft  
$\alpha$ is the angle of the winds aloft relative to the longitudinal axis of the aircraft.