Terms like "functional training" and "functional fitness" are buzzwords for exercises that train different muscle groups to work together. The goal of functional training is to train your body to better carry out the activities of everyday life. By contrast, standard weight training focuses on strengthening specific muscle groups using targeted moves with free weights or machines.
It is worth incorporating some aspects of functional training into your overall fitness routine. Remember, just because you are toned and taut doesn't mean that you can't hurt your back while hauling a heavy suitcase. Functional exercise has a neurological component that weight training on a machine lacks because the machine is supporting your body. That's fine when you are working on a specific area, but don't forget about functional fitness, because it can improve your coordination, thereby reducing your risk of injury.
One example of a functional training exercise is a bent-over row (instead of using a seated row machine). Here's how to do it: Lean over a bench and place your left hand and left knee on the bench for support. Hold a weight in your right hand that you might use for a biceps or triceps exercise. Let your right arm hang straight down, then lift it straight up so your elbow points towards the ceiling, with your upper arm parallel to the floor. This move works the back, shoulders and arms, and is similar to movements that most people do every day, such as lifting groceries or children out of cars.