Steering and Suspension
When we talk about steering and suspension components, we mean all the stuff that holds the wheels onto the rest of the car and keeps the tires in good contact with the road—both important features to have, if you don't want to accidentally drive into a bridge abutment. You can't really check most of these components yourself. Go to your mechanic and ask him to check the front and rear suspension components, the steering gear, and related parts, including ball joints and tie rods.
By the way, some vehicles with rear, independent suspensions have ball joints and related components that can fail catastrophically. It's a good idea to find out if your car has this kind of suspension. If it does, don't forget to mention this to your mechanic.