According to Jon Kabat-Zinn, "mindfulness means paying attention in a particular way; on purpose, in the present moment, and non judgmentally."
Explore some other definitions of mindfulness:
Why Practice Mindfulness? - from GreaterGood at UC Berkeley
Studies have shown that practicing mindfulness, even for just a few weeks, can bring a variety of physical, psychological, and social benefits. Here are some of these benefits, which extend across many different settings.