The triceps are actually any muscle groups that have three heads. When people normally mention the triceps, they are talking about that large muscle groups that are found under the upper arm, corresponding to the biceps that are found on the top of the upper arm that weightlifters normally contract.
The triceps are around 70% of your upper arm muscle and its primary functions are to straighten the arm and then bring it back towards the body. Mainly, tricep workouts are for aesthetic reasons, since these dreaded “saggy, slack-y arms” show a lack of definition that makes people appear older than they really are. Even Vince Delmonte mention these things in his no nonsense muscle building program.

One great exercise is the tricep kickback, which start in a kneeling position on the bench, the other foot on the floor. Support yourself with your corresponding arm on the bench. Keep yourself in a balanced position!
Arrange yourself so your torso becomes parallel to the floor with your abs tucked in and you looking straight ahead. With the dumb-bell in your free hand, raise your elbow until your upper arm is parallel to the ceiling, or higher. Then, lift the weight backward to straighten the arm without locking the elbow or changing the position of your elbow and wrist. Bring is slowly back into position.
Another great tricep workout is the dip. This classic exercise is done on a Roman chair or parallel bars, while the body is help straight upright. Do at least 5 reps and then add a weighted belt once you can go over five easily. Raise and lower yourself slowly, without bouncing or forcing. Keep the shoulders straight so they’re not pulled out of alignment.
Complete your workout with a diamond push-up with a clap after each rep. Position your hands with the index fingers and thumbs touching then push yourself up and clap before you return your hands to the same position. Work up to ten pushups before clapping!