I meditated over a period of 25 years, admittedly with more discipline in earlier years, before reaching the resolution of the yearning for self-definition that prompted my search. And even after self-realization, I didn't feel like I had any perspective on "What is meditation?" Then, a little more than a year later, a perspective drifted into my mind as I was drifting off to sleep one night.

Meditation is watching.

Like watching squirrels at play? Not exactly. Meditation is watching the mind.

Like watching our thoughts and feelings? That's a step in the right direction. But not exactly it, either. Meditation is watching the watching.

How do you do that? By watching the conflict going on in the mind without getting caught up in it. Easier said than done. It requires staying alert to the watching.

And then what? The watching will jump to a more interior view within the mind. Like a new eye opening? Not exactly. The more interior watching has been going on while our attention was on a more exterior watching.

What will I see? You'll see processes going on within the mind, such as decision-making. Like a factory with machinery operating or a computer with programs running.

And then what? You'll become aware of the biggest conflict, the main problem that the mind is trying to resolve: What am I? Where did I come from? What's my connection with the world and particularly with this body-mind? Will its death be my end?

Meditation is not drifting off into a pleasant state. There's no state more pleasant than dreamless sleep, and we go there every night, but it doesn't solve the problem. We return to the waking state without a resolution of the yearning for definition. (Substitute your own word or phrase for "definition": meaning, purpose, truth, reality, nirvana, heaven, oneness, love, etc.)

Meditation is reviewing life's traumas, the blows to our self-esteem, and letting them lead our search for the elusive self. Meditation is learning to monitor and control or sidestep the physical and mental obstacles to meditation. Meditation is watching until the watcher is known.

Source: http://www.selfdiscoveryportal.com/arMeditation.htm